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Pichia pastoris, a methylotrophic yeast, is an established system for the production of heterologous proteins, particularly biopharmaceuticals and industrial enzymes. To maximise and optimise the production of recombinant products, recent molecular research has focused on numerous issues including the design of expression vectors, optimisation of gene copy number, co-expression of secretory proteins such as chaperones, engineering of glycosylation and secretory pathways, etc. However, the physiological effects of different cultivation strategies are often difficult to separate from the molecular effects of the gene construct (e.g., cellular stress through over-expression or incorrect post-translational processing). Hence, overall system optimisation is difficult, even though it is urgently required in order to describe and understand the behaviour of new molecular constructs. This review focuses on particular aspects of recombinant protein production related to variations in biomass growth and their implications for strain design and screening, as well as on the concept of rational comparisons between cultivation systems for the development of specific production processes in bioreactors. The relationship between specific formation rates of secreted recombinant proteins, qp, and specific growth rates, µ, has been analysed in a conceptual attempt to compare different systems, particularly those based on AOX1/methanol and GAP/glucose, and this has now evolved into a pivotal concept for bioprocess engineering of P. pastoris.
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Técnicas de Cultivo de Célula/métodos , Pichia/crecimiento & desarrollo , Biomasa , Biotecnología , Cinética , Proteínas Recombinantes/biosíntesisRESUMEN
The current interest in microalgae as a sustainable source of next generation biofuels and other valuable substances is driving exploration of their use as unique biotechnological production systems. To design and optimise appropriate production strategies, the behaviour of particular microalgal species should be well characterised under different culture conditions. Thus, flow cytometric (FCM) methods, which are already well established in environmental and toxicological studies of microalgae, are also useful for analysing the physiological state of microalgae, and have the potential to contribute to the rapid development of feasible bioprocesses. These methods are commonly based on the examination of intrinsic features of individual cells within a population (such as autofluorescence or size). Cells possessing the desired physiological or morphological features, which are detectable with or without fluorescent staining, are counted or isolated (sorted) using an FCM device. The options for implementation of FCM in the development of biotechnological processes detailed in this review are (i) analysing the chemical composition of biomass, (ii) monitoring cellular enzyme activity and cell viability, and (iii) sorting cells to isolate those overproducing the target compound or for the preparation of axenic cultures.
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Biotecnología/métodos , Citometría de Flujo/métodos , Microalgas , Biocombustibles , Biomasa , Carbohidratos/análisis , Membrana Celular/química , Membrana Celular/metabolismo , Permeabilidad de la Membrana Celular , Tamaño de la Célula , Enzimas/análisis , Enzimas/metabolismo , Citometría de Flujo/instrumentación , Colorantes Fluorescentes , Lípidos/análisis , Microalgas/citología , Microalgas/metabolismo , Proteínas/análisisRESUMEN
Natural tools for recombinant protein production show technological limitations. Available natural promoters for gene expression in Pichia pastoris are either constitutive, weak or require the use of undesirable substances or procedures for induction. Here we show the application of deletion variants based on the well known methanol inducible AOX1 promoter and small synthetic promoters, where cis-acting elements were fused to core promoter fragments. They enable differently regulated target protein expression and at the same time to replace methanol induction by a glucose or glycerol feeding strategy. Trypsinogen, the precursor of the serine protease trypsin, was expressed using these different promoters. Depending on the applied promoter the production window (i.e. the time of increasing product concentration) changed significantly. In fedbatch processes trypsinogen yields before induction with methanol were up to 10 times higher if variants of the AOX1 promoter were applied. In addition, the starting point of autoproteolytic product degradation can be predetermined by the promoter choice.
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OBJECTIVE: The purpose of this article is to provide an overview of the current research on hallucinogen induced psychiatric disorders. In addition to LSD and psilocybin hallucinogens of biologic origin are increasingly used by adolescents and young adults. METHODS: Relevant literature and related articles were identified by means of a computerized MEDLINE search including the years 1997 - 2007. As keywords "hallucinogen induced psychosis", "hallucinogen induced flashback", "hallucinogen persisting perception disorder (HPPD)" were used. Finally, 64 journal articles and books out of 103 were included in the review. RESULTS: Acute psychotic syndromes in adolescents are rarely due to intoxications with hallucinogenic drugs. However, clinical relevance of flashback phenomena as post-hallucinogenic psychiatric disorder has to be disputed. Because of the high popularity of biogenic hallucinogens and LSD knowledge of intoxications and resulting psychiatric disorders as well as medical complications and therapeutical approaches are clinically important. Especially intoxications with drugs of herbal origin like tropanalcaloids play an important role in emergency situations.
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Alucinógenos/efectos adversos , Psicosis Inducidas por Sustancias/psicología , Adolescente , Adulto , Humanos , Dietilamida del Ácido Lisérgico , N,N-Dimetiltriptamina , Psilocibina , Recurrencia , Trastornos Relacionados con Sustancias/psicologíaRESUMEN
PURPOSE: The purpose of this study was a) to present a facilitated method for the preparation and workup of [11C]d-threo-methylphenidate ([11C]d-threo-MP) (a ligand that was shown to bind selectively to the presynaptic dopaminergic transporters) from [11C]methyliodide ([11C]CH3I), b) to demonstrate that the ligand can as well be produced by an alternative labeling method employing [11C]diazomethane as the labeling agent and c) to present biodistribution data for this tracer obtained in rats. METHODS: 11C-labeling with [11C]CH3I was performed using either [d-threo-1-(2-nitrophenylsulfanyl)piperidin-2-yl]phenyl-acetic acid (d-threo-N-NPS-ritalinic acid) under addition of sodium hydroxide as base or the previously prepared sodium salt of d-threo-N-NPS-ritalinic acid. The two approaches were compared with regard to radiochemical yield and purification procedures needed in order to obtain a sufficiently pure tracer solution for human use. For the alternative reaction pathway using [11C]diazo-methane as the labeling agent the reaction was performed with d-threo-N-NPS-ritalinic acid. The biodistribution of [11C]d-threo-MP was determined in rats at 5, 10 and 30 min post injection of the tracer. RESULTS: The application of the sodium salt of d-threo-N-NPS-ritalinic acid as precursor resulted in higher radiochemical yields than the use of the free acid under basic conditions, the yields were 20 +/- 8% and 6 +/- 3%, respectively for the final isolated product (based on [11C]CH3I starting activity). The alternative labeling approach by means of [11C]diazomethane as the labeling agent was demonstrated to give radiochemical yields of 76 +/- 8% (based on [11C]diazomethane starting activity, determined by HPLC analysis of the crude reaction mixture before final work-up) within shorter process times. Based on [11C]methane starting activity both approaches result in similar yields (17% and 15%, respectively) Biodistribution studies in rats revealed a low blood activity (0.09% injected dose/g (% ID/g)) at 5 min post injection (p.i.), as well as a relatively high liver uptake (15.9% ID at 30 min) compared to a lower kidney uptake (3.2% ID at 30 min). Brain uptake was 0.9% ID/g already 5 and 10 min p.i.. CONCLUSIONS: The application of the sodium salt of d-threo-N-NPS-ritalinic acid as precursor for the radiosynthesis of [11C]d-threo-MP reduces the amount of [11C]methanol formed from the reaction of [11C]CH3I with sodium hydroxide, that is added to generate the carboxylic anion of d-threo-N-NPS-ritalinic acid needed for labeling with [11C]CH3I. The purification process could be simplified (omission of one solid phase extraction step), resulting in an easily automated process for the production of the tracer. The preparation of [11C]d-threo-MP by means of [11C]diazomethane as the labeling agent appears to be an interesting alternative to the [11C]CH3I methods because of shorter overall process times and high labeling yields. Biodistribution data show a rapid extraction of the tracer from the blood pool. Tracer excretion seems to take place predominantly via the hepatic pathway since liver uptake at 30 min was considerably higher than kidney uptake. [11C]d-threo-MP exhibits a rapid and sufficiently high brain uptake in rats.
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Dopaminérgicos/farmacocinética , Marcaje Isotópico/métodos , Metilfenidato/farmacocinética , Radiofármacos/síntesis química , Radiofármacos/farmacocinética , Animales , Transporte Biológico , Encéfalo/metabolismo , Radioisótopos de Carbono , Dopamina/metabolismo , Dopaminérgicos/química , Proteínas de Transporte de Dopamina a través de la Membrana Plasmática , Inyecciones Intravenosas , Ligandos , Masculino , Metilfenidato/química , Tomografía de Emisión de Positrones , Radiofármacos/normas , Ratas , Ratas Sprague-Dawley , Distribución TisularRESUMEN
Patients with schizophrenia exhibit diminished prepulse inhibition (PPI) of the acoustic startle reflex and deficits in the attentional modulation of PPI. Pharmacological challenges with hallucinogens are used as models for psychosis in both humans and animals. Remarkably, in contrast to the findings in schizophrenic patients and in animal hallucinogen models of psychosis, previous studies with healthy volunteers demonstrated increased levels of PPI after administration of low to moderate doses of either the antiglutamatergic hallucinogen ketamine or the serotonergic hallucinogen psilocybin. The aim of the present study was to investigate the influence of moderate and high doses of the serotonergic hallucinogen N,N-dimethyltryptamine (DMT) and the N-methyl-D-aspartate antagonist S-ketamine on PPI and its attentional modulation in humans. Fifteen healthy volunteers were included in a double-blind cross-over study with two doses of DMT and S-ketamine. Effects on PPI and its attentional modulation were investigated. Nine subjects completed both experimental days with the two doses of both drugs. S-ketamine increased PPI in both dosages, whereas DMT had no significant effects on PPI. S-ketamine decreased and DMT tended to decrease startle magnitude. There were no significant effects of either drug on the attentional modulation of PPI. In human experimental hallucinogen psychoses, and even with high, clearly psychotogenic doses of DMT or S-ketamine, healthy subjects failed to exhibit the predicted attenuation of PPI. In contrast, PPI was augmented and the startle magnitude was decreased after S-ketamine. These data point to important differences between human hallucinogen models and both animal hallucinogen models of psychosis and naturally occurring schizophrenia.
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Atención/efectos de los fármacos , Antagonistas de Aminoácidos Excitadores , Alucinógenos , Ketamina , N,N-Dimetiltriptamina , Psicosis Inducidas por Sustancias/psicología , Reflejo de Sobresalto/efectos de los fármacos , Adulto , Método Doble Ciego , Femenino , Humanos , Masculino , Persona de Mediana Edad , Desempeño Psicomotor/efectos de los fármacos , Trastornos Relacionados con SustanciasRESUMEN
INTRODUCTION: Pharmacological challenges with hallucinogens are used as models for psychosis in experimental research. The state induced by glutamate antagonists such as phencyclidine (PCP) is often considered as a more appropriate model of psychosis than the state induced by serotonergic hallucinogens such as lysergic acid diethylamide (LSD), psilocybin and N,N-dimethyltryptamine (DMT). However, so far, the psychological profiles of the two types of hallucinogenic drugs have never been studied directly in an experimental within-subject design. METHODS: Fifteen healthy volunteers were included in a double-blind, cross-over study with two doses of the serotonin 5-HT2A agonist DMT and the glutamate N-methyl-D-aspartate (NMDA) antagonist (S)-ketamine. RESULTS: Data are reported for nine subjects who completed both experimental days with both doses of the two drugs. The intensity of global psychological effects was similar for DMT and (S)-ketamine. However, phenomena resembling positive symptoms of schizophrenia, particularly positive formal thought disorder and inappropriate affect, were stronger after DMT. Phenomena resembling negative symptoms of schizophrenia, attention deficits, body perception disturbances and catatonia-like motor phenomena were stronger after (S)-ketamine. DISCUSSION: The present study suggests that the NMDA antagonist model of psychosis is not overall superior to the serotonin 5-HT2A agonist model. Rather, the two classes of drugs tend to model different aspects or types of schizophrenia. The NMDA antagonist state may be an appropriate model for psychoses with prominent negative and possibly also catatonic features, while the 5-HT2A agonist state may be a better model for psychoses of the paranoid type.
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Antagonistas de Aminoácidos Excitadores/farmacología , Alucinógenos/farmacología , Ketamina/farmacología , N,N-Dimetiltriptamina/farmacología , Adulto , Cognición/efectos de los fármacos , Estudios Cruzados , Relación Dosis-Respuesta a Droga , Método Doble Ciego , Antagonistas de Aminoácidos Excitadores/química , Femenino , Alucinaciones/inducido químicamente , Alucinaciones/psicología , Humanos , Infusiones Intravenosas , Inyecciones Intravenosas , Ketamina/química , Masculino , Persona de Mediana Edad , Escalas de Valoración Psiquiátrica , Psicometría , Receptores de N-Metil-D-Aspartato/antagonistas & inhibidores , Psicología del Esquizofrénico , EstereoisomerismoRESUMEN
This paper describes the use of potentiometric titration to determine the relevant acid-base properties of 5-hydroxypyrazine-2-carboxylic acid (5OH-PYCA), an important intermediate in the production of tuberculostatics. The data obtained were used for calculation of the dissociation constants of 5OH-PYCA. It was found that 5OH-PYCA dissociates in two steps, with the corresponding dissociation constants pK (a1)=3.42 and pK (a2)=7.96, designating 5OH-PYCA as a medium weak acid (1st step). The distribution diagram of dissociated species and the buffer-strength diagram of 5OH-PYCA provide useful information about its behaviour at different pH. The ionic equilibria data obtained can be used for selection of the optimum pH for biotransformation of pyrazine-2-carboxylic acid (PYCA) and for prediction of pH changes during the biotransformation. These data can also be used for selection of the optimum pH for precipitating 5OH-PYCA in downstream processing. All computations have been optimized by mathematical modelling using Solver.
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The key to optimizing productivity during industrial fermentations is the ability to rapidly monitor and interpret the physiological state of single microbial cells in a population and to recognize and characterize different sub-populations. Here, a flow cytometry-based method for the reproducible detection of changes in membrane function and/or structure of recombinant E. coli JM101 (pSPZ3) expressing xylene monooxygenase (XMO), was developed. XMO expression led to compromised but not permeabilized cell membranes. This was deduced from the fact that recombinant cells only stained with ethidium bromide (EB) and not with propidium iodide (PI). During the glucose-limited fedbatch cultivation, an increase from 25% to 95% of EB-stained cells was observed, occurring between 2 and 5 h after induction. Control experiments confirmed that this increase was due to the recombinant protein production and not caused by any possible effects of varying substrate availability, high cell density, plasmid replication or the presence of the inducing agent. We hypothesize that the integration of the recombinant protein into the cell membrane physically disrupted the functionality of the efflux pumps, thus resulting in EB-staining of the recombinant cells. This method enabled us to detect changes in the physiological state of single cells 2-4 h before other indications of partial cell damage, such as unbalanced growth, acetate accumulation and an increased CO(2) production rate, were observed. This method therefore shows promise with respect to the further development of an early-warning system to prevent sudden productivity decreases in processes with recombinant E. coli expressing heterologous membrane proteins.
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Reactores Biológicos , Carbono/química , Membrana Celular/metabolismo , Escherichia coli/metabolismo , Citometría de Flujo/instrumentación , Citometría de Flujo/métodos , Acetatos/química , Membrana Celular/química , Medios de Cultivo/química , Medios de Cultivo/farmacología , Proteínas de Escherichia coli/química , Etidio/farmacología , Fermentación , Colorantes Fluorescentes/farmacología , Glucosa/metabolismo , Microbiología Industrial/instrumentación , Microbiología Industrial/métodos , Proteínas de la Membrana/química , Microscopía Fluorescente , Oxigenasas/metabolismo , Propidio/química , Propidio/farmacología , Proteínas Recombinantes/química , Factores de TiempoRESUMEN
A near-infrared reflection spectroscopy (NIRS) method was developed to determine the total content of kavapyrones, kavain and water in dry extracts of Piper methysticum Forst. (kava kava, Piperaceae). Based on the recorded spectra and the reference data, performed by HPLC and Karl Fischer titration, a chemometrical analysis was calculated using PLS 2 algorithm. In general, good calibration statistics are obtained for the prediction of the different contents presenting high correlation coefficients (r(2) > 0.9913) and low root mean square errors of prediction (RMSEP < 0.094%). Usually the main water bands are "cut out" of the spectra to improve the model, however this is associated with the loss of relevant spectroscopic information. Thus, the entire spectrum including the OH bands is used, as these are not only found in water but also in the kavapyrones. The use of this new strategy succeeds in overcoming the difficulties in NIRS and establishes NIRS as a valid alternative in the routine quality control of plant extracts.
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Kava , Pironas/análisis , Espectroscopía Infrarroja Corta/métodos , Extractos Vegetales/análisis , Agua/análisisRESUMEN
An efficient method to characterise complex plant extracts is described using the example of Piper methysticum Forst. (kava; Piperaceae). The method is based on the on-line coupling of high-performance liquid chromatography to a new detection technique: coordination ion spray-mass spectrometry (CIS/MS). CIS/MS is a universal, novel ionisation technique improving selectivity as well as sensitivity. Charged complexes were formed through addition of central complexing ions such as sodium, silver and cobalt. The advantages of CIS/MS detection compared with the electrospray ionisation detection are discussed. The experimental set-up and the application of this simple and robust technique is described to show the its various fields of application in the analysis of plant extracts.
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Cromatografía Líquida de Alta Presión/métodos , Kava/química , Espectrometría de Masas/métodos , Extractos Vegetales/análisis , Pironas/análisis , Extractos Vegetales/químicaRESUMEN
3,4-Methylenedioxymethamphetamine (MDMA) has recently been hypothesized to be effective against the symptoms of Parkinson's disease. Therefore we tested the effects of MDMA-derivatives in the rotational behavioural model. Male Sprague Dawley rats were lesioned unilaterally with 6-hydroxydopamine at the medial forebrain bundle. MDMA was administered at doses of 2.5, 5.0 and 10.0 mg/kg, its derivatives N-Methyl-1-(1,3-benzodioxol-5-yl)-2-butananamine (MBDB), 3,4-Methylenedioxy-N-ethylamphetamine (MDE) and 3,4-Methylenedioxyamphetamine (MDA) at 5.0 mg/kg respectively. All substances induced ipsilateral rotations, MDA being the most effective. MDMA induced rotations were attenuated by the selective serotonin reuptake inhibitor Citalopram but were only slightly reduced by pre-treatment with the selective serotonin synthesis inhibitor PCPA (para-chlorophenylalanine). The effects of MDMA can therefore not fully be explained by serotonin release or by dopaminergic activity of the drugs.
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3,4-Metilenodioxianfetamina/análogos & derivados , Dopamina/metabolismo , Alucinógenos/farmacología , Haz Prosencefálico Medial/efectos de los fármacos , Haz Prosencefálico Medial/fisiopatología , N-Metil-3,4-metilenodioxianfetamina/farmacología , 3,4-Metilenodioxianfetamina/farmacología , Adrenérgicos/farmacología , Animales , Apomorfina/farmacología , Conducta Animal/efectos de los fármacos , Citalopram/farmacología , Fenclonina/farmacología , Lateralidad Funcional , Masculino , Modelos Animales , Oxidopamina/farmacología , Enfermedad de Parkinson/fisiopatología , Ratas , Ratas Sprague-Dawley , Rotación , Antagonistas de la Serotonina/farmacología , Inhibidores Selectivos de la Recaptación de Serotonina/farmacologíaRESUMEN
Hallucinogenic drug-induced states are considered as models for acute schizophrenic disorders (experimental psychoses). In a double-blind study with healthy volunteers we investigated the influence of the serotonergic hallucinogen psilocybin, the ecstasy-like drug 3,4-methylenedioxyethylamphetamine (MDE), the stimulant d- methamphetamine and placebo on covert orienting of spatial attention (n = 8 in each group). Reaction times were prolonged after ingestion of psilocybin > MDE, but not after d-methamphetamine. In addition, subjects on psilocybin exhibited particularly slow reaction times in invalid trials at short cue target intervals and failure of response inhibition in valid trials at long cue target intervals for right visual field targets. Despite some methodological limitations, these results are in line with both bilateral impairment of disengagement of attention and a lateralized impairment of inhibition of return (IOR) in productive psychotic states. Additional investigations with larger samples, different hallucinogenic substances (serotonergic agonists vs. NMDA antagonists) and different dose regimens are needed in order to further explore the suggested relationship between visuospatial attentional dysfunction and acute psychotic conditions.
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3,4-Metilenodioxianfetamina/análogos & derivados , Atención/efectos de los fármacos , Alucinógenos/efectos adversos , Psilocibina/efectos adversos , Percepción Espacial/efectos de los fármacos , Percepción Visual/efectos de los fármacos , 3,4-Metilenodioxianfetamina/efectos adversos , Adulto , Estimulantes del Sistema Nervioso Central/efectos adversos , Método Doble Ciego , Femenino , Alucinógenos/farmacología , Humanos , Masculino , Metanfetamina/efectos adversos , Persona de Mediana Edad , Psilocibina/farmacología , Tiempo de ReacciónRESUMEN
A quantitative near-infrared reflectance spectroscopy (NIRS) method was established for the determination of two major constituents (hyperforin and I3,II8-biapigenin) in St. John's wort extracts. Hyperforin was chosen due to the fact that it is found in a concentration range from 1 to 5%, a common one for NIRS determinations. I3,II8-Biapigenin on the other hand was selected as a constituent with very low concentrations (0.1-0.7%) but an extensive chromophore that allows very precise measurements in the ultraviolet (UV) and thus exact reference values that are vital for proper NIRS calibrations. Reference measurements were performed by reversed-phase high performance liquid chromatography (HPLC), determining the constituents' content in 35 pharmaceutical dry extracts of different origins. The reference method was validated according to the ICH guideline Q2B. Using partial-least squares (PLS) regression a multivariate calibration was done for the two ingredients each (PLS1). Satisfactory calibration statistics were obtained for hyperforin with a root mean square error of calibration (RMSEC) of 0.17 and a root mean square error of prediction (RMSEP) of 0.22 at a concentration range from 1 to 6% in the dry extracts. Due to the very low concentrations of I3,II8-biapigenin the accuracy of prediction is somewhat lower. However, it is possible to obtain very good results and reliable prediction by dividing the concentration range at 0.35%. The study emphasizes the potential of NIRS as a rapid and highly effective alternative method to conventional quantitative analysis of plant extracts.
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Apigenina , Biflavonoides , Hypericum/química , Compuestos Bicíclicos con Puentes , Calibración , Cromatografía Líquida de Alta Presión , Flavonoides/análisis , Análisis Multivariante , Floroglucinol/análogos & derivados , Extractos Vegetales/análisis , Estándares de Referencia , Espectrofotometría Ultravioleta , Espectroscopía Infrarroja Corta , Terpenos/análisisRESUMEN
This paper describes a convenient and practice method for quantitation of surfactant phospholipids (1,2-dipalmitoyl-3-sn-phosphatidyl choline [DPPC] and 1-palmitayl-2-oleyl-3-sn-phosphatidyl glycerol [POPG]) in a recombinant surfactant lyophile (Venticute) by high-performance, thin-layer chromatography (HPTLC) with video densitometry. DPPC and POPG were extracted from Venticute-lyophile using methanol. Separation from the other active ingredients and excipients was accomplished by HPTLC on silica gel F254 plates with a mixture of chloroform, methanol, glacial acetic acid, and water as development solvent. Postchromatographic derivatization by dipping in copper sulphate/phosphoric acid reagent and subsequent heating shows grey-brown bands on a light blue background. These were detected with the video densitometer in the VIS range, and with scanning densitometry at 365 nm. Linear calibration in a working range of 0.7-1.3 microg DPPC and 0.35-0.65 microg POPG was demonstrated by integrating the area under the peaks. Good results were obtained with recovery experiments. When compared to classical slit scanning densitometry, video densitometry represents a fast alternative to quantitate thin-layer chromatograms in surfactant phospholipid analysis.
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1,2-Dipalmitoilfosfatidilcolina/análisis , Fosfatidilgliceroles/análisis , DensitometríaRESUMEN
In a randomised double-blind trial the subjective, neuropsychological and brain activation effects of the two enantiomers of the MDMA (ecstasy-) like drug N-ethyl-3,4-methylenedioxyamphetamine (MDE) were studied in five normal subjects using functional magnetic resonance imaging (fMRI). (S)-MDE produced elevated mood, impairments in conceptually driven cognition and marked right frontal activation. In contrast, (R)-MDE produced increased depression, enhanced visual feature processing, and activation of visual cortical and left frontal areas. Plasma concentrations were higher for the (R)-enantiomer. The so-called entactogenic effects of MDE are likely to be caused by the (S)-enantiomer, whereas (R)-MDE appears to be responsible for neurotoxic effects.
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3,4-Metilenodioxianfetamina/análogos & derivados , 3,4-Metilenodioxianfetamina/farmacología , Encéfalo/efectos de los fármacos , Cognición/efectos de los fármacos , Pruebas Neuropsicológicas , 3,4-Metilenodioxianfetamina/sangre , Análisis de Varianza , Encéfalo/fisiología , Cognición/fisiología , Método Doble Ciego , Humanos , Imagen por Resonancia Magnética/métodos , Masculino , Psicometría , Estadísticas no Paramétricas , EstereoisomerismoRESUMEN
The selective neurotoxic action of the abused drug 3,4-methylenedioxymethamphetamine (MDMA) on the serotonergic axons ascending from the dorsal raphe nucleus (DRN) is well known. The present study examined the long-term effects of subchronic MDMA treatment on rat brain tissue contents of catecholaminergic neurotransmitters. Two and four weeks after cessation of repeated MDMA treatment (ten consecutive days, 20 mg/kg/day), the tissue neurotransmitter concentrations were measured by means of electrochemical detected HPLC in several forebrain areas and DRN. We found reduced serotonin levels in the whole forebrain at both instants of time. In nucleus accumbens (NAC), the noradrenaline levels were also decreased, whereas dopamine levels were increased 4 weeks after treatment. It is concluded that MDMA causes changes of monoamine transmitter levels outlasting cessation of drug intake for at least 4 weeks. Decreased noradrenaline and/or serotonin may subsequently cause the augmentation of dopamine in NAC, a structure crucially involved in motivation circuits. With exception of transmitter alterations in the NAC, the post drug effects are opposite to the acute effects of MDMA and may underlie the psychiatric changes after MDMA intake in humans.
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Dopamina/metabolismo , Alucinógenos/farmacología , N-Metil-3,4-metilenodioxianfetamina/farmacología , Neostriado/efectos de los fármacos , Norepinefrina/metabolismo , Núcleo Accumbens/efectos de los fármacos , Serotonina/metabolismo , Animales , Axones/efectos de los fármacos , Axones/metabolismo , Axones/patología , Esquema de Medicación , Ácido Hidroxiindolacético/metabolismo , Masculino , Neostriado/metabolismo , Núcleo Accumbens/metabolismo , Corteza Prefrontal/efectos de los fármacos , Corteza Prefrontal/metabolismo , Núcleos del Rafe/efectos de los fármacos , Núcleos del Rafe/metabolismo , Núcleos del Rafe/patología , Ratas , Ratas Sprague-Dawley , Degeneración Retrógrada/inducido químicamente , Degeneración Retrógrada/patología , Degeneración Retrógrada/fisiopatología , Trastornos Relacionados con Sustancias/metabolismo , Trastornos Relacionados con Sustancias/patología , Trastornos Relacionados con Sustancias/fisiopatología , Factores de TiempoRESUMEN
A chiral HPLC method has been developed for the ecstasy analogue (R,S)-N-ethyl-3,4-methylenedioxyamphetamine (MDE) and its metabolites o-glucuronyl-(R,S)-N-ethyl-4-hydroxy-3-methoxyamphetamine (HME) and (R,S)-3,4-methylenedioxyamphetamine (MDA) in human plasma. The chiral discrimination of the compounds was carried out with an enantioselective HPLC method using beta-cyclodextrin in the mobile phase for MDE and MDA and a chiral protein phase (chiral-CBH) for HME. MDE and MDA were detected fluorimetrically at 322 nm, while the major metabolite HME was selectively determined by electrochemical detection at +600 mV. After hydrolysis of the conjugates using beta-glucuronidase/arylsulfatase and solid-phase extraction with a cation-exchange phase for sample preparation high recovery rates of more than 95% were yielded. The limit of quantitation for the enantiomers of MDE and its metabolites in plasma were between 1.2 (MDA) and 16 ng/ml (HME) and the relative method standard deviations (V(xO), Table 1) were less than 3%. The methods described have been used successfully in the enantioselective quantitation of the compounds in plasma samples obtained from six healthy volunteers in a clinical study after oral administration of 140 mg racemic MDE hydrochloride. Significant differences were found in the plasma concentrations of the examined stereoisomers. Whereas the R-enantiomer of the parent substance, MDE, was predominant in the plasma samples investigated, higher plasma concentrations of the S-enantiomers of the metabolites MDA and HME were measured.
Asunto(s)
3,4-Metilenodioxianfetamina/análogos & derivados , 3,4-Metilenodioxianfetamina/sangre , Cromatografía Líquida de Alta Presión/métodos , 3,4-Metilenodioxianfetamina/metabolismo , 3,4-Metilenodioxianfetamina/farmacocinética , Humanos , N-Metil-3,4-metilenodioxianfetamina/química , Sensibilidad y EspecificidadRESUMEN
An efficient HPTLC--UV/FTIR coupling procedure is presented for the separation and rapid identification of flurazepam hydrochloride and its related substances in bulk powder and capsules. An optimized mobile phase was developed for the separation on specialized plates for HPTLC--FTIR in situ measurement containing a proportion of 50% magnesium tungstate. The proposed procedure shows several advantages to the related compound test of the pharmacopoeia, e.g. baseline separation of the known impurities and detection of the substances as peaks in the UV, Gram-Schmidt or window chromatograms. Furthermore, unambiguous identification is obtained by postrun extraction of the DRIFT spectra and comparison with reference spectra in the library. Quantification of the related compounds was carried out densitometrically. This method shows that the current resurgence of interest in modern instrumental TLC is rightful based on the flexibility and efficiency of this analytical method.
Asunto(s)
Cromatografía en Capa Delgada/métodos , Flurazepam/química , Hipnóticos y Sedantes/química , Cápsulas , Cromatografía Líquida de Alta Presión/métodos , Polvos , Espectroscopía Infrarroja por Transformada de Fourier/métodosRESUMEN
To increase product safety of pharmaceuticals, a new near-infrared (NIR) method for the online identity check of pharmaceutical finished products was validated. The method comprises a new near-infrared device VisioNIR (Uhlmann VisioTec GmbH, Laupheim, Germany) and the appropriate evaluation statistics. The VisioNIR is applied to the packaging line and provides the possibility to perform a 100% product identity check at full line speed. The products were analyzed applying near-infrared spectroscopy (900-1700 nm) in reflectance mode. The scanned products were two widely used pharmaceuticals named Capsule A (containing 300 mg of paracetamol and 250 mg of chlorzoxazone) and Capsule B (containing 500 mg of paracetamol and 30 mg of codeine phosphate). In order to demonstrate the fitness of the VisioNIR the obtained data were compared with the data acquired by Foss NIRSystems 6500 spectrometer (NIRSystems, Silver Springs, MD). The results obtained by the VisioNIR evaluation statistics were compared with the results obtained by the commonly used principal component analysis. The advantages and the suitability of the method are discussed. In this new configuration NIR spectroscopy offers an excellent possibility for non-destructive 100% online quality control of pharmaceutical products.