RESUMEN
We reviewed the three reference toxicokinetic studies commonly used to suggest innocuity of aluminum (Al)-based adjuvants. A single experimental study was carried out using isotopic 26Al (Flarend et al., 1997). This study ignored adjuvant cell capture. It was conducted over a short period of time (28 days) and used only two rabbits per adjuvant. At the endpoint, Al retention was 78% for aluminum phosphate and 94% for aluminum hydroxide, both results being incompatible with quick elimination of vaccine-derived Al in urines. Tissue distribution analysis omitted three important retention sites: the injected muscle, the draining lymph node and bone. Two theoretical studies have evaluated the potential risk of vaccine Al in infants, by reference to the oral Minimal Risk Level (MRL) extrapolated from animal studies. Keith et al., 2002 used a too high MRL (2mg/kg/d), an erroneous model of 100% immediate absorption of vaccine Al, and did not consider renal and blood-brain barrier immaturity. Mitkus et al. (2011) only considered absorbed Al, with erroneous calculations of absorption duration. They ignored particulate Al captured by immune cells, which play a role in systemic diffusion and the neuro-inflammatory potential of the adjuvant. MRL they used was both inappropriate (oral Al vs injected adjuvant) and far too high (1mg/kg/d) with regard to experimental studies of Al-induced memory and behavioral changes. Both paucity and serious weaknesses of these studies strongly suggest that novel experimental studies of Al adjuvants toxicokinetics should be performed on the long-term, including post-natal and adult exposures, to ensure innocuity and restore population confidence in Al-containing vaccines.
Asunto(s)
Adyuvantes Inmunológicos/farmacocinética , Hidróxido de Aluminio/farmacocinética , Aluminio/farmacocinética , Compuestos de Aluminio , Animales , Humanos , Fosfatos , Conejos , Valores de Referencia , Distribución Tisular , Toxicocinética , VacunasRESUMEN
Previous studies have shown that the striatum expresses very low levels of Na+/Cl(-)-dependent "orphan" transporter Rxt1 transcripts but contains high levels of protein. This study investigated the origin of Rxt1 expression in rat striatum. Striatal Rxt1 contents assessed by immunocytochemistry or western blotting were found to be significantly reduced after corticostriatal denervation but not after striatal or thalamic lesion with kainic acid or selective 6-hydroxydopamine-induced nigrostriatal deafferentation. Corticostriatal neurons retrogradely labeled by intrastriatal fluorogold injections were shown to express Rxt1 mRNA. Combination of anterograde biotin-dextran amine labeling of the corticostriatal pathway with Rxt1 immunogold detection at the ultrastructural level demonstrated the presence of Rxt1 in about one-third of the corticostriatal synaptic terminals and in numerous unidentified synaptic terminals. All the Rxt1-positive terminals formed asymmetrical contacts on spines. These data provide evidence that striatal Rxt1 immunoreactivity is mainly of extrinsic origin and more specifically associated with the corticostriatal pathway. Rxt1 appears as a selective presynaptic marker of synapses formed by presumably excitatory amino acid afferents, but it segregates a subclass of these synapses, thereby revealing a functional heterogeneity among excitatory amino acid systems.
Asunto(s)
Proteínas Portadoras/genética , Corteza Cerebral/citología , Cuerpo Estriado/citología , Proteínas de Transporte de Membrana , Terminaciones Nerviosas/química , Proteínas del Tejido Nervioso/genética , Vías Aferentes , Animales , Autorradiografía , Biotina/análogos & derivados , Química Encefálica , Corteza Cerebral/química , Cuerpo Estriado/química , Desnervación , Dextranos , Agonistas de Aminoácidos Excitadores , Colorantes Fluorescentes , Hibridación in Situ , Ácido Kaínico , Masculino , Microscopía Electrónica , Terminaciones Nerviosas/ultraestructura , Oxidopamina , Proteínas de Transporte de Neurotransmisores en la Membrana Plasmática , ARN Mensajero/análisis , Ratas , Ratas Sprague-Dawley , Ratas Wistar , Sustancia Negra/citología , Simpaticolíticos , Sinapsis/química , Tálamo/citologíaRESUMEN
Evidence that nuclear-encoded RNAs are present inside mitochondria has been reported from a wide variety of organisms, and is presumed to be due to import of specific cytosolic RNAs. In plants, the first examples were the mitochondrial leucine transfer RNAs of bean. In all cases, the evidence is circumstantial, based on hybridization of the mitochondrial RNAs to nuclear and not mitochondrial DNA. Here we show that transgenic potato plants carrying a leucine tRNA gene from bean nuclear DNA contain RNA transcribed from the introduced gene both in the cytosol and inside mitochondria, providing proof that the mitochondrial leucine tRNA is derived from a nuclear gene and imported into the mitochondria. The same bean gene carrying a 4 bp insertion in the anticodon loop was also expressed in transgenic potato plants and the transcript found to be present inside mitochondria, suggesting that this natural RNA import system could eventually be used to introduce foreign RNA sequences into mitochondria.
Asunto(s)
Fabaceae/genética , Mitocondrias/metabolismo , Mutagénesis Sitio-Dirigida , Plantas Medicinales , Aminoacil-ARN de Transferencia/metabolismo , ARN de Transferencia de Leucina/genética , Secuencia de Bases , Fraccionamiento Celular , Clonación Molecular , Genes de Plantas , Cinética , Datos de Secuencia Molecular , Oligodesoxirribonucleótidos , Plantas Modificadas Genéticamente , ARN de Transferencia de Leucina/metabolismo , Fracciones Subcelulares/metabolismo , Transcripción GenéticaRESUMEN
The efficacy of an extract of Pygeum africanum in the treatment of micturitional disorders due to benign prostatic hyperplasia was tested in a multicentre double-blind trial versus placebo. Capsules containing 50 mg of Pygeum africanum extract or placebo were administered at a dosage of 1 capsule in the morning and 1 capsule in the evening over a period of 60 days. 263 patients were included in this study, which was carried out in 8 centres in Germany, France, and Austria. Evaluation was mainly based on quantitative parameters such as residual urine, uroflowmetry and the precise monitoring of diurnal and nocturnal pollakiuria. Treatment with the Pygeum africanum extract led to a marked clinical improvement: a comparison of the quantitative parameters showed a significant difference between the Pygeum africanum group and the placebo group with respect to therapeutic response. The characteristic subjective symptoms of micturitional disorders, which were evaluated by the patients in a qualitative manner, were also significantly improved by administration of Pygeum africanum extract. Overall assessment at the end of therapy, showed that micturition improved in 66% of the patients treated with Pygeum africanum extract, as compared with an improvement of 31% in the placebo group. The difference was significant at the statistical level of p less than 0.001. During therapy with Pygeum africanum extract, gastrointestinal side effects occurred in 5 patients. Treatment was discontinued in three of those cases.