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1.
J Forensic Sci ; 68(4): 1425-1430, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37254609

RESUMO

Colchicine has been widely used in the treatment of acute gout over the years, but it has a narrow therapeutic index, and overdose can be life threatening. A method using ultra-high-performance liquid chromatography-tandem mass spectrometry system was applied in two fatal cases of colchicine poisoning in this study to the determination of colchicine in blood. In case 1, a 19-year-old man suffered from depression and ingested 160 colchicine tablets (each 0.5 mg). The concentration of colchicine in his blood samples showed a fluctuating trend and kept above the therapeutic steady-state concentration for 5 days. In case 2, a 70-year-old female patient with a history of gout and chronic colchicine intake ingested five times the usual dose of colchicine (5 mg) and died after 12 days of medical care, with 5 ng/mL of colchicine in her blood sample. Our findings suggest that the delayed elimination and accumulation in humans after colchicine overdose could keep the concentration of colchicine maintaining above the therapeutic steady-state concentration for many days before dying, probably along with a fluctuating trend.


Assuntos
Overdose de Drogas , Gota , Intoxicação , Humanos , Masculino , Feminino , Idoso , Adulto Jovem , Adulto , Colchicina , Cromatografia Líquida de Alta Pressão/métodos , Ingestão de Alimentos
2.
Forensic Sci Int ; 347: 111683, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37068373

RESUMO

PURPOSE: Knowing and analyzing the characteristics and trends of forensic toxicology cases in a certain area is particularly important for a local government to establish an effective prevention and control system. The purpose of this work was to summarize data from forensic toxicology cases received by the Academy of Forensic Sciences (AFS) in 2021. METHODS: As requested by the police or according to the details of cases, samples were systematically screened or analyzed by various methods. Liquid chromatography-tandem mass spectrometry and gas chromatography-mass spectrometry were used to identify medicinal drugs, drugs of abuse, pesticides, poison gases, etc. RESULTS: AFS received a total of 17,758 cases in 2021, of which 314 cases underwent autopsy. The main cause of death was sudden death, and the manner of death was mainly accident. Among 13,744 drug abuse cases, the number of positive cases was 1721, with a positive rate of 12.5%, and synthetic cannabinoids were the most frequently detected substances. In 3640 traffic cases, 85.3% of drivers were suspected of drunk driving. In 103 poisoning cases, hydrogen sulfide poisoning and pesticide suicide account for a large proportion. In drug-facilitated crimes, zolpidem was the most frequently tested component. In 55 case of dog poisonings, the main poisons were cyanides and succinylcholine, and the main poisoning tools were poisonous baits and poisonous syringe darts. CONCLUSIONS: This study profiles the toxicological characteristics of forensic toxicological cases conducted at the AFS in 2021 and provides a scientific basis for poisoning cases and drug abuse prevention.


Assuntos
Praguicidas , Intoxicação , Transtornos Relacionados ao Uso de Substâncias , Suicídio , Animais , Cães , Toxicologia Forense/métodos , Estudos Retrospectivos , Medicina Legal , Intoxicação/diagnóstico
3.
Forensic Sci Int ; 337: 111350, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35709589

RESUMO

Drug abuse/misuse is now a major global problem affecting public health as well as economic and social stability. This study presents a retrospective view of the prevalence of drugs in hair. Reasons for hair testing include the need for law enforcement to test suspicious individuals and the need for employers in specific industries to test their employees. Toxicology analysis results were reviewed for a total of 19,275 hair samples requested for drug abuse/misuse analysis at the Academy of Forensic Science over 29 months from February 2019 to June 2021. Drugs and their metabolites in hair samples were analyzed by liquid chromatography - tandem mass spectrometry. In the study, the 19,275 hair samples were screened for a total of 62 illegal drugs, which were divided into three categories: illegal-drugs (I), medication (II), and new psychoactive substances (III). These three categories contain 11, 29 and 22 drugs respectively. In these hair samples, 4852 (25.2 %) tested positive for one or more drugs. Among them, the positive rate of category I was the highest (48.7 %), followed by category II (28.5 %), and category III (22.7 %). Over all, the positive rate of male users (26.2 %) was higher than that of female users (23.7 %), and most of them were young people (25-44 years old). Illegal-drugs (morphine, etc.) had the highest positive rate. Under the influence of some certain factors, the drug abuse situation will also undergo corresponding changes. The results can provide a scientific knowledge database which can help in the prevention of drug abuse.


Assuntos
Drogas Ilícitas , Transtornos Relacionados ao Uso de Substâncias , Adolescente , Adulto , Cromatografia Líquida/métodos , Feminino , Toxicologia Forense/métodos , Cabelo/química , Humanos , Drogas Ilícitas/análise , Masculino , Estudos Retrospectivos , Detecção do Abuso de Substâncias/métodos , Transtornos Relacionados ao Uso de Substâncias/diagnóstico , Transtornos Relacionados ao Uso de Substâncias/epidemiologia
4.
J Chromatogr A ; 1663: 462743, 2022 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-34974369

RESUMO

Synthetic cannabinoids (SCs) are new psychoactive substances that function as endocannabinoid CB1 and CB2 receptor agonists. Abuse of SCs can lead to symptoms such as confusion, dizziness, and even death. At present, Synthetic cannabinoids constitute one of the largest groups of new psychoactive substances and become popular recreational drugs of abuse for their psychoactive properties. The continuous transformation of SCs also leads to an endless emergence of new types. An efficient, high-throughput screening method is therefore very important for their identification. This paper describes a liquid chromatography-high resolution mass spectrometry (LC-HRMS) method for simultaneously screening 179 SCs and 80 SC metabolites in blood and urine. Simple acetonitrile was used to precipitate the blood and urine proteins, and the supernatants obtained after centrifugation were analyzed. The LC-HRMS run time was 20 min. The mass spectrometer used an ESI source with a scanning range of m/z 100-1000. LC-HRMS provided accurate mass, retention time, and fragment ions for qualitative analysis. The method validation results showed that the limits of detection (LODs) for over 80% compounds were 5 ng/mL in blood and urine samples. At low concentrations (50 ng/mL), 229 compounds (95.8%) in the blood showed recoveries of more than 50%, and 232 compounds (97.1%) had matrix effects greater than 80%. In the urine, 219 compounds (91.6%) had recoveries above 50%, and the matrix effects of 234 compounds (97.9%) were greater than 80%. This method was successfully applied to actual forensic cases.


Assuntos
Canabinoides , Drogas Ilícitas , Cromatografia Líquida , Limite de Detecção , Espectrometria de Massas , Detecção do Abuso de Substâncias
5.
Front Chem ; 8: 610312, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33330406

RESUMO

Methyl 2 -[ [ 1- (5- fluoropentyl) indole - 3- carbonyl] amino] -3, 3- dimethyl - butanoate (5F-MDMB-PICA) is a new synthetic cannabinoid characterized by valinate or tert-leucinate moieties. In recent years, 5F-MDMB-PICA has been abused in the form of "spice-like" herbal incenses or electronic cigarette oil. A UHPLC-MS/MS method was developed to detect 5F-MDMB-PICA and its metabolites in human hair. Approximately 20 mg of hair was weighed and pulverized with methanol below 4°C. After ultrasonication, centrifugation and filtration, 200 µL of supernatant was placed into an autosampler vial and analyzed on a Waters Acquity UPLC HSS T3 column (100 mm × 2.1 mm, 1.8 µm particle size) using an acetonitrile-20 mmol/L ammonium acetate (0.1% formic acid, 5% acetonitrile) gradient with a run time of 8 min. The limit of detection (LOD) ranged from 0.5 to 5 pg/mg, and the lower limit of quantitation (LLOQ) ranged from 1 to 5 pg/mg. The method was shown to be linear over a concentration range of 1-200 pg/mg. The linear correlation (R 2) of the calibration curves for all analytes was >0.999. The accuracy varied from 95.4 to 107.4%, while the intra- and inter-day precision RSD values were 0.7-10.6% and 1.7-12.2%, respectively. Recoveries were within the range of 61.1-93.3%, and matrix effects were in the range of 19.1-102.6%. The validated method was successfully applied to the identification and quantification of 5F-MDMB-PICA and its metabolites in hair from authentic forensic cases.

6.
J Forensic Leg Med ; 72: 101963, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32452453

RESUMO

PURPOSE: The dried urine spots (DUSs) technique is increasing continuously as an easy sampling method for monitoring substance abuse due to its advantages of stability and convenience regarding transport and storage. 5-Methoxy-N,N-diisopropyltryptamine (5-MeO-DIPT) is a new type of tryptamine hallucinogen, the use of which has been banned in many countries. And according to the previous research, 5-MeO-DIPT is not stable in urine. In order to improve its stability, an LC-MS/MS method for determining 5-MeO-DIPT in DUSs was developed. METHOD: 10 µl urine was spotted on Whatman FTATM classic card, then extracted with 200 µl methanol, and liquid chromatography-tandem mass spectrometry in positive ion multiple reaction monitoring mode was utilized for analysis. RESULTS: The LOD and LLOQ of the method were 0.1 ng/ml and 0.2 ng/ml, respectively. The accuracy and precision were 98.2%-103.9% and 2.7%-8.5%, respectively. It was found that the stability of 5-MeO-DIPT in DUSs was better than the stability of 5-MeO-DIPT in urine stored at 25 °C. Moreover, this method was also applied to detect 5-MeO-DIPT in the urine of individuals known to have used 5-MeO-DIPT. It was found that the concentrations of 5-MeO-DIPT were 0.3-2.3 ng/ml, which were lower than those obtained via GC-Orbitrap-MS. The small volume of urine required (10 µl), combined with the simplicity of the analytical technique, makes this an useful procedure for the screening of drug of abuse.


Assuntos
5-Metoxitriptamina/análogos & derivados , Cromatografia Líquida/métodos , Alucinógenos/urina , Detecção do Abuso de Substâncias , Transtornos Relacionados ao Uso de Substâncias/urina , Espectrometria de Massas em Tandem/métodos , 5-Metoxitriptamina/urina , Dessecação , Estabilidade de Medicamentos , Toxicologia Forense/métodos , Humanos , Limite de Detecção
7.
J Forensic Sci ; 65(2): 563-569, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31498435

RESUMO

A method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) to simultaneously quantify amphetamines, opiates, ketamine, cocaine, and metabolites in human hair is described. Hair samples (50 mg) were extracted with methanol utilizing cryogenic grinding. Calibration curves for all the analytes were established in the concentration range 0.05-10 ng/mg. The recoveries were above 72%, except for AMP at the limit of quantification (LOQ), which was 48%. The accuracies were within ±20% at the LOQ (0.05 ng/mg) and between -11% and 13.3% at 0.3 and 9.5 ng/mg, respectively. The intraday and interday precisions were within 19.6% and 19.8%, respectively. A proficiency test was applied to the validated method with z-scores within ±2, demonstrating the accuracy of the method for the determination of drugs of abuse in the hair of individuals suspected of abusing drugs. The hair concentration ranges, means, and medians are summarized for abused drugs in 158 authentic cases.


Assuntos
Cromatografia Líquida , Cabelo/química , Entorpecentes/análise , Detecção do Abuso de Substâncias/métodos , Transtornos Relacionados ao Uso de Substâncias/diagnóstico , Espectrometria de Massas em Tandem , Adulto , Anfetaminas/análise , Cocaína/análise , Feminino , Toxicologia Forense/métodos , Humanos , Ketamina/análise , Limite de Detecção , Masculino , Pessoa de Meia-Idade , Alcaloides Opiáceos/análise
8.
J Anal Toxicol ; 44(6): 596-600, 2020 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-31776560

RESUMO

In this study, the relationships between the concentrations of R/S-methamphetamine (MA) and its metabolite R/S-amphetamine (AP), the AP/MA ratio in hair samples, and MA dependence were investigated by performing segmental hair analysis in MA users. Authentic hair samples collected from 10 chronic MA abusers were cut into 1-cm sections (a total of 120 segments). The concentrations of MA and AM enantiomers were quantitatively measured by the LC-MS-MS method. The S-MA concentrations ranged from 1.17 to 256.41 ng/mg and the S-AP concentrations ranged from 0.11 to 23.31 ng/mg in the 120 segments. S-MA and S-AP were the most common analytes identified in hair; no R-MA or R-AP was found. The S-AP/S-MA ratios ranged from 0.03 to 0.32, indicating that the subjects primarily consumed S-MA rather than R-MA or AP. The S-AP/S-MA ratios in the long hair of all chronic MA abusers showed some variation, but there was an overall trend of gradual increase from the distal to the proximal end. This trend was independent of the drug concentrations. Therefore, we could conclude that the AP/MA ratios increased with the duration of MA abuse, and a higher AP/MA ratio suggested high MA dependence. There was no chiral conversion of MA or AP in the hair matrix. The segmental hair analysis showed that all subjects continuously used S-MA, and some users showed an increase in drug dose or the frequency of use.


Assuntos
Anfetamina/análise , Cabelo/química , Drogas Ilícitas/análise , Metanfetamina/análise , Detecção do Abuso de Substâncias , Cromatografia Líquida , Análise do Cabelo , Humanos , Espectrometria de Massas
9.
Drug Test Anal ; 12(4): 472-484, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31875650

RESUMO

Hair analysis is useful for documenting long-term exposure to drugs. The potential of hair analysis for therapeutic drug monitoring within the forensic field has been studied, but reference values for some antidepressants and antipsychotics in the hair of individuals undergoing chronic therapy are still lacking. In the present study, a method was developed and validated for the determination of 23 analytes, including antidepressants, antipsychotics, and related metabolites, in human hair by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Hair samples (10 mg) were extracted with a 25:25:50 (v/v/v) mixture of methanol/acetonitrile/2 mM ammonium formate (8% acetonitrile, pH 5.3) utilizing cryogenic grinding. The present method demonstrated sufficient selectivity, robustness, and accuracy. Sixteen analytes in hair were reported in 46 psychiatric patients receiving fixed drug dosages. To the best of our knowledge, the hair concentrations of perphenazine and norolanzapine, as well as the concentrations of amisulpride, aripiprazole and its metabolite dehydroaripiprazole, olanzapine, and sulpiride, in hair from individuals receiving fixed dosages is reported for the first time. A significant relationship between the administered dose and the concentration in the proximal hair segment was found only for clozapine, norclozapine, and chlorpromazine. The results confirmed that the idea of using hair concentrations to monitor a daily dose is inapplicable.


Assuntos
Antidepressivos/farmacocinética , Antipsicóticos/farmacocinética , Monitoramento de Medicamentos/métodos , Cabelo/metabolismo , Esquizofrenia/tratamento farmacológico , Adulto , Antidepressivos/administração & dosagem , Antidepressivos/análise , Antipsicóticos/administração & dosagem , Antipsicóticos/análise , Cromatografia Líquida/métodos , Cabelo/química , Humanos , Limite de Detecção , Masculino , Pessoa de Meia-Idade , Esquizofrenia/metabolismo , Espectrometria de Massas em Tandem/métodos
10.
Forensic Sci Int ; 284: 153-160, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29408724

RESUMO

Methamphetamine (MA) and amphetamine (AM) are widely abused drugs. These compounds contain a chiral center, and their enantiomers exhibit different pharmacologic, pharmacokinetic, and metabolic properties due to differences in binding affinities to their receptor sites. Until now, there was a lack of information on the decline in the concentration of drugs in hair after abstinence. A simple procedure for the chiral separation and determination of methamphetamine (MA) and its metabolite amphetamine (AM) enantiomers by LC-MS/MS in hair samples has been developed and fully validated. The LODs and LLOQs were 0.02ng/mg and 0.05ng/mg for all analytes, respectively. This method was successfully applied to both real hair specimens from chronic MA users and after the discontinuation of MA. The concentration of total MA, and total AM in fifty-eight authentic hair specimens ranged from 7.8ng/mg to 521.0ng/mg, and from 0.3ng/mg to 84.0ng/mg, respectively. Both enantiomers of MA and/or AM were detected in seven of fifty-eight authentic hair specimens. Hair specimens were from thirteen women with a known history of MA abuse, who went to a rehabilitation center and ceased consuming MA (for 4-5 months). The S-isomers of MA and AM were detected in all the 5-6cm segments. Both enantiomers of MA were detected in nine of the 5-6cm segments and the enantiomers of AM were found in only five of the nine samples. Assuming a hair growth rate of 1cm/month, the mean hair elimination half-lives of S-MA, R-MA, S-AM, and R-AM were 0.64(95% CI, 0.46-0.96), 0.58(95% CI, 0.41-0.93), 0.62(0.49-0.88), and 0.50 months (95% CI, 0.42-0.56), respectively. With the developed method, R/S-MA and R/S-AM could be detected in the hair of former drug users for approximately 4 months after abstinence. S-MA is the most commonly found analyte in hair segments and is principally used by abusers. Our results suggest that to evaluate the discontinuation of MA abuse after a 6-month period of abstinence, a 3-cm proximal hair segment should be free of MA at the SOHT proposed cut-off level.


Assuntos
Transtornos Relacionados ao Uso de Anfetaminas/reabilitação , Anfetamina/análise , Cabelo/química , Metanfetamina/análise , Adulto , Cromatografia Líquida , Feminino , Meia-Vida , Humanos , Espectrometria de Massas , Pessoa de Meia-Idade , Adulto Jovem
11.
J Anal Toxicol ; 42(5): 330-336, 2018 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-29378027

RESUMO

Phosphine is an insecticide for the fumigation of grains, animal feed, and leaf-stored tobacco, and it was used as a rodenticide in bulk grain stores. Phosphine poisoning may occur after accidental inhalation of phosphine, sometimes leading to death. Analysis of phosphine and its metabolites in postmortem specimens from seven fatal cases was conducted in this study, as well as postmortem specimens collected from rabbits exposed to phosphine. The total phosphine in postmortem specimens was analyzed by headspace gas chromatography coupled with mass spectrometry. Diagnosis of aluminum phosphide poisoning was made after postmortem toxicological analysis and confirmed by police investigation. The deaths of the children occurred after inhalation of phosphine generated from aluminum phosphide contacting moisture in the air in all seven fatal cases. The concentration of total phosphine in the biological fluids and tissues of victims ranged from 0.2 to 4.7 µg/mL (µg/g). Animal experiments demonstrated that the phosphine generated from aluminum phosphide could rapidly cause death. The toxicological analysis of postmortem specimens provides useful information in diagnosis of aluminum phosphide poisoning in forensic science. As an important fumigation pesticide, aluminum phosphide deserves special attention, especially since there is no specific antidote and there is a high fatality rate.


Assuntos
Compostos de Alumínio/toxicidade , Exposição por Inalação/efeitos adversos , Inseticidas/toxicidade , Intoxicação por Organofosfatos/metabolismo , Fosfinas/análise , Fosfinas/toxicidade , Rodenticidas/toxicidade , Animais , Biotransformação , Cadáver , Criança , Pré-Escolar , Feminino , Fumigação/efeitos adversos , Humanos , Rim/química , Rim/patologia , Fígado/química , Fígado/patologia , Pulmão/química , Pulmão/patologia , Masculino , Intoxicação por Organofosfatos/diagnóstico , Intoxicação por Organofosfatos/mortalidade , Intoxicação por Organofosfatos/patologia , Fosfinas/sangue , Fosfinas/urina , Coelhos , Estudos Retrospectivos , Distribuição Tecidual , Toxicocinética
12.
Fa Yi Xue Za Zhi ; 23(2): 120-2, 129, 2007 Apr.
Artigo em Chinês | MEDLINE | ID: mdl-17619459

RESUMO

OBJECTIVE: To establish an analytical method for the determination of GHB in beverages using GC/MS and LC/MS/MS. METHODS: After beverage samples with GHB-d6 as the internal standard were extracted with ethyl acetate, then the extracts were derivatized with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA), at last the derivateized extracts analyzed by gas chromatography- mass spectrometry. After beverage samples with GHB-d6 as the internal standard were diluted by mobile phase then directly analyzed by LC/MS/MS. Results The limit of detection was 0.2 microg/mL and both relative standard deviations for between-day and within-day assays were < 8.54% in GC/MS. The limit of detection was 2 microg/mL and both relative standard deviations for between-day and within-day assays were <8.62% in LC/MS/MS. Conclusion These methods of qualitative and quantitative analysis were found to be sensitive, accurate, rapid and suitable for the forensic toxicology to test of GHB in real cases.


Assuntos
Bebidas/análise , Cromatografia Gasosa-Espectrometria de Massas/métodos , Oxibato de Sódio/análise , Anestésicos Intravenosos/análise , Medicina Legal/métodos , Humanos , Concentração de Íons de Hidrogênio , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Oxibato de Sódio/química , Detecção do Abuso de Substâncias/métodos
13.
Fa Yi Xue Za Zhi ; 23(5): 349-52, 2007 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-18175574

RESUMO

OBJECTIVE: To establish a liquid chromatography-tandem mass chromatography (LC-MS/MS) method for the simultaneous screening for 22 poisonous alkaloids in blood. METHODS: This method involves a liquid-liquid extraction (LLE) followed by liquid chromatography-tandem mass spectrometry with multi-ple-reaction monitoring (MRM). After blood was extracted with buprenorphine as the internal standard, the target compounds were analyzed with LC-MS/MS-ESI in the positive ionization mode. RESULTS: Identification was based on the compound's retention time and two precursor-to-product ion transitions. The limits of detection ranged from 0.1 ng/mL to 20 ng/mL in blood. CONCLUSION: The method was sufficiently selective and sensitive to detect poisonous alkaloids and can be applied in forensic and clinical toxicology.


Assuntos
Alcaloides/sangue , Cromatografia Líquida/métodos , Espectrometria de Massas em Tandem/métodos , Aconitina/sangue , Alcaloides/química , Colchicina/sangue , Medicina Legal , Humanos , Sensibilidade e Especificidade , Estricnina/sangue
14.
Forensic Sci Int ; 126(2): 153-61, 2002 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-12084493

RESUMO

The presence of therapeutic drugs and their metabolites in the hair of psychiatric patients was investigated using gas chromatography (GC)-mass spectroscopy (MS)-electron ionization (EI) and GC-MS-chemical ionization (CI). In hair samples tested from 35 subjects, carbamazepine, amitriptyline, doxepin, trihexyphenidyl, chlorpromazine, chlorprothixene, trifluoperazine, clozapine and haloperidol were detected, with maximal concentrations of 22.5, 57.7, 183.3, 15.6, 68.2, 30.0, 36.8, 59.2 and 20.1 ng/mg of hair sample, respectively. Chlorpromazine and clozapine concentrations in the hair were found to be dependent on the dosage used and their correlation coefficients were 0.8047 (P<0.001, n=16) and 0.7097 (P<0.001, n=16), respectively. Segmental analysis demonstrated that there was a correlation between the history of subject's drug exposure and the distribution of drug along the hair shaft. Our results also show that drug analysis in hair may provide useful information about drug treatment and the history of usage, and that drugs can be detected in normally kept hair for at least 16 months after intake.


Assuntos
Antidepressivos/análise , Antipsicóticos/análise , Medicina Legal , Cabelo/química , Adulto , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Masculino , Transtornos Mentais/tratamento farmacológico , Pessoa de Meia-Idade , Transtornos Relacionados ao Uso de Substâncias/diagnóstico
15.
Ai Zheng ; 21(12): 1335-40, 2002 Dec.
Artigo em Chinês | MEDLINE | ID: mdl-12520743

RESUMO

BACKGROUND & OBJECTIVE: Methotrexate has been used to treat malignant tumor for 50 years. Different mechanisms of methotrexate resistance has been known in various kinds of leukemias. Because of individualized chemotherapy according to different drug metabolism in different leukemia patients, the treatment became more reasonable and scientific and the treatment effect has been gradually improved. However, there was few report about its drug resistance mechanism in lymphoma. This study was designed to establish Burkitt's lymphoma methotrexate resistant cell strain--Namlwa 12/MTX and study its resistant mechanism. METHODS: Namlwa 12/MTX resistant cell strain was established by repeated impulsed exposure to methotrexate. The difference of the methotrexate effect on Namlwa 12/MTX and Namlwa cell strains were evaluated with MTT method. The level of dihydrofolate reductase (DHFR) mRNA expression was assayed with RT-PCR. The function of the reduced folate carrier (RFC) were tested with 3H-MTX labeling and counted with beta-liquid scintillation counter. The capacity to form the polyglutamate methotrexate (MTXPG) in these cell strains was assayed with 3H-MTX labeling and high pressure liquid chromatography (HPLC) separation. RESULTS: More than 20 times methotrexate resistance was found in Namalwa 12/MTX cell strain in comparison with the Namalwa cell strain. This resistance was not associated with the dysfunction of the RFC, but was closely associated with the amount of MTXPG formed. The amount of total MTXPG (MTXPG1-6) formed in these 2 cell strains was (1583 +/- 26) pmol/10(9) tumor cells and (4453 +/- 236) pmol/10(9) tumor cells, respectively (P < 0.05), while the amount of long chain MTXPG (MTXPG4-6) formed only accounted for 5.5% and 25.4% of the MTXPG1-6, respectively (P < 0.05). The level of DHFR mRNA expression was gradually increased with the formation of the drug resistance in Namalwa 12/MTX. CONCLUSION: Synthesizing difficulty of MTXPG and over-expression of DHFR mRNA level result in methotrexate resistance in Namalwa 12/MTX cell strain.


Assuntos
Antimetabólitos Antineoplásicos/farmacologia , Proteínas de Transporte/metabolismo , Resistencia a Medicamentos Antineoplásicos/fisiologia , Proteínas de Membrana Transportadoras , Metotrexato/análogos & derivados , Metotrexato/farmacologia , Ácido Poliglutâmico/análogos & derivados , Tetra-Hidrofolato Desidrogenase/metabolismo , Linfoma de Burkitt/patologia , Divisão Celular/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Metotrexato/análise , Ácido Poliglutâmico/análise , RNA Mensageiro/metabolismo , Proteína Carregadora de Folato Reduzido , Tetra-Hidrofolato Desidrogenase/genética , Células Tumorais Cultivadas
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