RESUMO
In 1996, U.S. Food and Drug Administration regulations mandated the fortification of enriched cereal-grain products with folic acid, thereby emphasizing the need for validated methods for total folates in foods, particularly cereal products. The AOAC Official Methods (944.12, 960.46) currently used for the analysis of folate in foods for compliance purposes are microbiological methods. When the fortification regulations were finalized, no Official AOAC or Approved AACC methods for folate in cereal-grain products were in place. The AOAC Official Method (992.05) for folic acid in infant formula does not incorporate important improvements in the extraction procedure and was not considered suitable for the analysis of folates in foods in general. A microbiological assay protocol using a trienzyme extraction procedure was prepared and submitted for comments to 40 laboratories with recognized experience in folate analysis. On the basis of comments, the method was revised to have the conjugase (gamma-glutamyl-carboxy-peptidase) treatment follow a protease treatment, to include the use of cryoprotected inoculum, and to include the spectroscopic standardization of the standard and optional use of microtiter plates. Thirteen laboratories participated in a collaborative study of 10 required and 10 optional cereal-grain products, including flour, bread, cookies, baking mixes, and ready-to-eat breakfast cereals. The majority of the participating laboratories performed the assay by the standard test tube method; others used the microtiter plate modification for endpoint quantitation with equal success. For the required products, the relative standard deviation between laboratories (RSD(R)) ranged from 7.4 to 21.6% for 8 fortified (or enriched) products compared with expected (Horwitz equation-based) values of 11-20%. RSD(R) values were higher (22.7-52.9%) for 2 unfortified cereal-grain products. For the optional products, the RSD(R) ranged from 1.8 to 11.2% for 8 fortified products. RSD(R) values were higher (27.9-28.7%) for 2 unfortified cereal-grain products. Based on the results of the collaborative study, the microbiological assay with trienzyme extraction is recommended for adoption as Official First Action.
Assuntos
Técnicas de Química Analítica/métodos , Grão Comestível/metabolismo , Análise de Alimentos/métodos , Alimentos Fortificados , Lactobacillus/metabolismo , Espectrofotometria/métodos , Automação , Pão , Ácido Fólico/análise , Ácido Fólico/química , Deficiência de Ácido Fólico/prevenção & controle , Guias como Assunto , Humanos , Concentração de Íons de Hidrogênio , Laboratórios , Nefelometria e Turbidimetria , Política Nutricional , Oxigênio/metabolismo , Controle de Qualidade , Reprodutibilidade dos TestesRESUMO
Glial cell line-derived neurotrophic factor (GDNF) is a potent and specific neurotrophic factor for dopaminergic neurons. GDNF has been previously shown to protect dopaminergic neurons from lesion-induced degeneration in vivo. In this study we investigated the effect of GDNF on 6-hydroxydopamine (6-OHDA)-treated dopaminergic neurons in vitro. In dissociated cultures of embryonic rat mesencephalon, 6-OHDA exhibited a dose-dependent cytotoxicity on tyrosine hydroxylase (TH)-immunoreactive neurons. After pre-treatment with GDNF, however, 6-OHDA-induced loss of dopaminergic neurons was effectively reduced. It has been shown recently that GDNF signals through the receptor tyrosine kinase Ret and the GDNF receptor-alpha (GFR-alpha). By RT-PCR, we found both Ret- and GFR-alpha-genes to be expressed in the cultured mesencephalic cells. We propose that the neuroprotective effect of GDNF on 6-OHDA-treated dopaminergic neurons in vitro is most likely mediated by functional Ret receptor signaling pathways.
Assuntos
Sobrevivência Celular/efeitos dos fármacos , Dopamina/fisiologia , Proteínas de Drosophila , Mesencéfalo/citologia , Fatores de Crescimento Neural , Proteínas do Tecido Nervoso/farmacologia , Neurônios/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Oxidopamina/toxicidade , Proteínas Proto-Oncogênicas/genética , Receptores Proteína Tirosina Quinases/genética , Animais , Células Cultivadas , Embrião de Mamíferos , Regulação da Expressão Gênica/efeitos dos fármacos , Fator Neurotrófico Derivado de Linhagem de Célula Glial , Receptores de Fator Neurotrófico Derivado de Linhagem de Célula Glial , Neurônios/citologia , Neurônios/metabolismo , Oxidopamina/antagonistas & inibidores , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-ret , Ratos , Receptores Proteína Tirosina Quinases/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais/efeitos dos fármacos , Tirosina 3-Mono-Oxigenase/metabolismoRESUMO
Intra-abdominal and intrathoracic misplacement is a possible complication after insertion of a chest drain but perforation of the left ventricle has very rarely been described. We report on a 57-year-old woman who had to be resuscitated due to circulatory insufficiency subsequent to cardiogenic and hemorrhagic shock after the insertion of a chest drain for the treatment of a postpneumonic pleural effusion. During surgery perforation of the left ventricle with hemopericardium was found. Despite an initially unfavorable situation the patient recovered well.
Assuntos
Tubos Torácicos/efeitos adversos , Corpos Estranhos/diagnóstico , Corpos Estranhos/terapia , Parada Cardíaca/etiologia , Parada Cardíaca/terapia , Ventrículos do Coração/lesões , Derrame Pleural/terapia , Atividades Cotidianas/classificação , Tamponamento Cardíaco/diagnóstico , Tamponamento Cardíaco/terapia , Comportamento Cooperativo , Ecocardiografia , Feminino , Seguimentos , Humanos , Hipóxia-Isquemia Encefálica/diagnóstico , Hipóxia-Isquemia Encefálica/etiologia , Hipóxia-Isquemia Encefálica/terapia , Comunicação Interdisciplinar , Pessoa de Meia-Idade , Equipe de Assistência ao Paciente , Modalidades de Fisioterapia , Reabilitação Vocacional , Síndrome do Desconforto Respiratório/diagnóstico , Síndrome do Desconforto Respiratório/etiologia , Síndrome do Desconforto Respiratório/terapiaRESUMO
Effects of estrogen hormones on lipid peroxidation (LPO) were examined in rat brain homogenates (RBHs), hippocampal HT 22 cells, rat primary neocortical cultures, and human brain homogenates (HBHs). Dose-response curves indicated half-maximal effective concentrations (EC50) of 5.5 and 5.6 mM for iron-induced LPO in RBHs and HT 22 homogenates. Incubation of living rat primary neocortical cultures with iron resulted in an EC50 of 0.5 mM, whereas culture homogenates showed an EC50 of 1.2 mM. Estrogen hormones reduced LPO in all systems: In RBHs, estrone inhibited iron-induced LPO to 74.1 +/- 5.8% of control levels (17beta-estradiol: 71.3 +/- 0.1%) at a concentration of 10 microM. In hippocampal HT 22 cell homogenates, levels of LPO were reduced to 74.8 +/- 5.5% by estrone and to 47.8 +/- 6.2% by 17beta-estradiol. In living neocortical cultures, 17beta-estradiol decreased iron-induced LPO to 79.2 +/- 4.8% and increased the survival of cultured neuronal cells. Of the other steroid compounds tested (corticosterone, progesterone, testosterone), only progesterone decreased LPO in HT 22 cell homogenates. In HBHs, LPO was dose-dependently increased by iron concentrations from 2.7 to 6.0 mM. Incubation with estrogens resulted in a dose-dependent inhibition of LPO to 53.8 +/- 8.6% with 10 microM 17beta-estradiol, whereas estrone failed to affect iron-induced LPO to a significant extent. Nonestrogenic steroids, including hydrocortisol, did not show significant effects on LPO in HBHs.
Assuntos
Encéfalo/metabolismo , Corticosterona/farmacologia , Estradiol/farmacologia , Peroxidação de Lipídeos/efeitos dos fármacos , Neocórtex/metabolismo , Neurônios/metabolismo , Animais , Encéfalo/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Cloretos , Compostos Férricos/farmacologia , Humanos , Cinética , Masculino , Malondialdeído/análise , Neurônios/citologia , Neurônios/efeitos dos fármacos , Progesterona/farmacologia , Ratos , Ratos Wistar , Testosterona/farmacologia , Substâncias Reativas com Ácido Tiobarbitúrico/análise , Vitamina E/farmacologiaRESUMO
Amphetamineanalogs have emerged as popular recreational drugs of abuse. The number of reports of these substances producing severe acute toxicity and death is increasing. In 'Ecstasy' -associated deaths, focal necrosis in the liver and individual myocytic necrosis has been reported. Furthermore, serotonergic and dopaminergic neuronal cell damage has been observed in experimental amphetamine intoxication in laboratory animals. Here we demonstrate that subchronic exposure to D-amphetamine, methamphetamine, methylenedioxyamphetamine, and methylenedioxymethamphetamine ('Ecstasy') results in significant neurotoxicity in rat neocortical neurons in vitro. This neuronal cell death is accompanied by endonucleosomal DNA cleavage and differential expression of anti- and proapoptotic bcl-xL/S splice variants. In addition, we observed pronounced induction of cell stress-associated transcription factor c-jun and translation initiation inhibitor p97 after amphetamine treatment. These data support that the neurotoxic effects of different amphetamines are extended to rat neocortical neurons and that apoptotic pathways are involved in amphetamine-induced neurotoxicity.