RESUMEN
UNLABELLED: Multislice computed tomography (MSCT) is a non-invasive and validated technique to detect coronary stenoses. Some questions remain about its accuracy to detect coronary stenoses (CS), especially for asymptomatic patients (P) when a prior stress test isn't conclusive. METHODS: MSCT was performed among 45 asymptomatic men (mean age: 58,3 +/- 16), with a high ten year risk of fatal cardiovascular disease (SCORE 2003 data for low-risk regions of Europe), without any previous coronary history and with previous non conclusive exercise testing. When significant (> 50%) CS was suspected at MSCT, an angiocoronarography (AC) was done. RESULTS: Eighteen MSCT were normal, unsignificant CS (< 50%) were detected on 14 MSCT and significant coronary stenoses (SCS) for 13 P. Among this 13 P, 19 SCS were identified: 2 SCS of left main coronary artery (CA), 9 of the left descending CA, 6 of the right CA and 2 of the left circumflex CA. 13 CS were confirmed at AC. Finally, because of critical angiographic lesions +/- ischemia at nuclear tomoscintigraphy (NT), 9 P had coronary revascularization (7 catheter based, 2 surgical bypass), 4 P had medical treatment. DISCUSSION: Benefits of this preliminary study are obvious: 9 coronary revascularization/45 P. However, the place of MSCT for the screening of CS is uncertain, but may be usefull as a complement for the screening of coronary arterial disease.
Asunto(s)
Estenosis Coronaria/diagnóstico , Tomografía Computarizada por Rayos X/métodos , Anciano , Anciano de 80 o más Años , Angiografía Coronaria , Estenosis Coronaria/terapia , Prueba de Esfuerzo , Humanos , Masculino , Persona de Mediana Edad , Revascularización Miocárdica , Factores de RiesgoRESUMEN
We measured the effects of slow-release caffeine (SRC) and melatonin (Mlt) on sleep and daytime sleepiness after a seven-time zone eastbound flight. In a double-blind, randomized, placebo-controlled study, each of three groups of nine subjects was given either 300 mg SRC on recovery day 1 (D1) to D5 (0800) or 5 mg Mlt on preflight D-1 (1700), flight day D0 (1600), and from D1 to D3 (2300), or placebo (Pbo) at the same times. Nighttime sleep was evaluated by polysomnography and daytime sleepiness from measurements of sleep latencies and continuous wrist actigraphy. Compared with baseline, we found a significant rebound of slow-wave sleep on night 1 (N1) to N2 under Pbo and Mlt and a significant decrease in rapid eye movement sleep on N1 (Pbo) and N1-N3 (Mlt). Sleepiness was objectively increased under Pbo (D1-D6) and Mlt (D1-D3). SRC reduced sleepiness but also tended to affect sleep quality until the last drug day. In conclusion, both drugs have positive effects on some jet lag symptoms after an eastbound flight: SRC on daytime sleepiness, and Mlt on sleep.
Asunto(s)
Anticonvulsivantes/administración & dosificación , Cafeína/administración & dosificación , Estimulantes del Sistema Nervioso Central/administración & dosificación , Síndrome Jet Lag/tratamiento farmacológico , Melatonina/administración & dosificación , Adulto , Temperatura Corporal , Femenino , Humanos , Masculino , Persona de Mediana Edad , Sueño/efectos de los fármacos , Fases del Sueño/efectos de los fármacosRESUMEN
In this review we sum-up the knowledge about bZIP G-box binding factors (GBFs), which possess an N-terminal, proline-rich domain. The GBF has been one of the most extensively studied transcription factor family. Based on protein sequence homology with yeast and animal basic leucine-zipper (bZIP) transcription factors, bioinformatic studies have identified their main structural domains (proline-rich, basic and leucine-zipper), which have been further functionally characterized by in vitro and in vivo experiments. Recent reports have led to the discovery of other GBF-specific short amino-acid sequences that may take part in the regulation of gene expression by post-transcriptional modifications or interaction with other proteins such as bZIP enhancing factors or plant 14-3-3-like proteins. We identified a GBF region, called the 'multifunctional mosaic region', that may be implicated in cytoplasmic retention, translocation to the nucleus and regulation of transcription. We also identified many conserved protein motifs that suggest a modular structure for GBFs. At the whole plant level, GBFs have been shown to be involved in developmental and physiological processes in response to major cues such as light or hormones. Nevertheless, it remains difficult to assign a physiological role to a particular GBF protein modular structure. Finally, bringing together these different aspects of GBF studies we propose a model describing the puzzling transduction pathway involving GBFs from cytoplasmic events of signal transduction to the regulation of gene expression in the nucleus.
Asunto(s)
Proteínas de Unión al ADN/metabolismo , Plantas/metabolismo , Factores de Transcripción/metabolismo , Secuencia de Aminoácidos , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico , Quinasa de la Caseína II , Proteínas de Unión al ADN/química , Proteínas de Unión al ADN/genética , Factores de Unión a la G-Box , Regulación de la Expresión Génica de las Plantas , Datos de Secuencia Molecular , Fosforilación , Plantas/genética , Conformación Proteica , Proteínas Serina-Treonina Quinasas/metabolismo , Homología de Secuencia de Aminoácido , Factores de Transcripción/química , Factores de Transcripción/genéticaRESUMEN
The enzyme encoded by the strictosidine synthase (Str) gene catalyses a key step in the biosynthesis of therapeutically valuable terpenoid indole alkaloids. In Catharanthus roseus the Str gene was shown to be regulated by a wide variety of signals including auxin, methyl jasmonate and fungal elicitors in cell suspension cultures and by tissue-specific control in plant organs. The Str promoter contains a functional G-box (CACGTG) cis-regulatory sequence. In order to understand better the mechanisms involved in the regulation of Str gene expression, we isolated the C. roseus cDNAs encoding G-box binding factors Crgbf1 and Crgbf2. The binding specificity of their protein products CrGBF1 and CrGBF2 was analysed by competitive electrophoresis mobility and saturation binding assays. CrGBF1 had a high binding specificity for class I G-boxes including the Str G-box. CrGBF1 showed a lower affinity for class II G-boxes and for the G-box-like element (AACGTG) found in the tryptophan decarboxylase (Tdc) gene which encodes another enzyme involved in TIA biosynthesis. CrGBF2 showed a high affinity for all types of G-boxes tested and to a lesser extent for the Tdc G-box-like element. Transient bombardment experiments demonstrated that both CrGBF1 and CrGBF2 can act in vivo as transcriptional repressors of the Str promoter via direct interaction with the G-box. These data indicate that GBFs may play functional role in the regulation of expression of the terpenoid indole alkaloid biosynthetic gene Str.
Asunto(s)
Liasas de Carbono-Nitrógeno/genética , Proteínas de Unión al ADN/genética , Plantas/genética , Proteínas Represoras/genética , Factores de Transcripción/genética , Secuencia de Aminoácidos , Sitios de Unión/genética , Unión Competitiva , Northern Blotting , Southern Blotting , ADN/genética , ADN/metabolismo , ADN Complementario/química , ADN Complementario/genética , ADN Complementario/aislamiento & purificación , ADN de Plantas/genética , Proteínas de Unión al ADN/metabolismo , Factores de Unión a la G-Box , Regulación Enzimológica de la Expresión Génica , Regulación de la Expresión Génica de las Plantas , Datos de Secuencia Molecular , Células Vegetales , Regiones Promotoras Genéticas , Unión Proteica , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , ARN de Planta/genética , ARN de Planta/metabolismo , Alineación de Secuencia , Análisis de Secuencia de ADN , Homología de Secuencia de Aminoácido , Distribución Tisular , Factores de Transcripción/metabolismoRESUMEN
Some long work or shift work schedules necessitate an elevated and prolonged level of vigilance and performance but often result in sleep deprivation (SD), fatigue and sleepiness, which may impair efficiency. This study investigated the effects of a slow-release caffeine [(SRC) at the daily dose of 600 mg] on vigilance and cognitive performance during a 64 h continuous wakefulness period. Sixteen healthy males volunteered for this double-blind, randomised, placebo controlled, two-way crossover study. A total of 300-mg SRC or placebo (PBO) was given twice a day at 21:00 and 9:00 h during the SD period. Vigilance was objectively assessed with continuous electroencephalogram (EEG), the multiple sleep latency tests (MSLT) and wrist actigraphy. Cognitive functions (information processing and working memory), selective and divided attention were determined with computerised tests from the AGARD-NATO STRES Battery (Standardised Tests for Research with Environmental Stressors). Attention was also assessed with a symbol cancellation task and a Stroop's test; alertness was appreciated from visual analogue scales (VAS). Tests were performed at the hypo (02:00-04:00 h, 14:00-16:00 h) and hypervigilance (10:00-12:00 h, 22:00-00:00 h) periods during SD. Central temperature was continuously measured and safety of treatment was assessed from repeated clinical examinations. Compared with PBO, MSLT showed that SRC subjects were more vigilant from the onset (P=0.001) to the end of SD (P < 0.0001) whereas some cognitive functions were improved till the thirty third of SD but others were ameliorated through all the SD period and alertness was better from the thirteenth hour of SD, as shown by Stroop's test (P=0.048). We showed that 300-mg SRC given twice daily during a 64-h SD is able to antagonize the impairment produced on vigilance and cognitive functions.
Asunto(s)
Nivel de Alerta/efectos de los fármacos , Cafeína/farmacología , Estimulantes del Sistema Nervioso Central/farmacología , Cognición/efectos de los fármacos , Privación de Sueño/inducido químicamente , Vigilia/efectos de los fármacos , Adulto , Temperatura Corporal/fisiología , Cafeína/administración & dosificación , Cafeína/efectos adversos , Estimulantes del Sistema Nervioso Central/administración & dosificación , Estimulantes del Sistema Nervioso Central/efectos adversos , Estudios Cruzados , Preparaciones de Acción Retardada , Método Doble Ciego , Humanos , Masculino , Factores de TiempoRESUMEN
Desynchronization of circadian rhythmicity resulting from rapid travel through at least four time zones leads to symptoms known in everyday English as jet-lag. The most detrimental effect of jet-lag is fatigue with poor alertness and psychomotor performance. Severity is subject to individual variation in susceptibility (morning/evening typology, age,...) and environmental factors (direction of travel, number of time zones crossed, psychosocial environment...). Many measures used to prevent or reduce jet lag are inappropriate or ineffective and some may even be dangerous, such as use of melatonin. One of the most reliable preventive techniques consists of reinforcing social synchronizers by maintaining exposure to sunlight and social activity. Only two drugs currently available on the market can be recommended, i.e. non-benzodiazepinic hypnotics which induce high quality sleep to allow quick recovery and a new time-release caffeine agent which has been shown to prolong psychomotor performance.
Asunto(s)
Ritmo Circadiano , Viaje , Cafeína/uso terapéutico , Estimulantes del Sistema Nervioso Central/uso terapéutico , Ritmo Circadiano/efectos de los fármacos , Ritmo Circadiano/fisiología , Humanos , Hipnóticos y Sedantes/uso terapéutico , Melatonina/fisiología , Melatonina/uso terapéutico , Desempeño Psicomotor , Factores de Riesgo , Luz SolarRESUMEN
Omission of 2,4-D from culture medium during one subculture of Catharanthus roseus cells, strain C20, resulted in an increased alkaloid accumulation, without effect on growth. Alkaloid accumulation, rather than growth, seemed to be more sensitive to 2,4-D. 2,4-D inhibited alkaloid accumulation essentially during growth phase, but its inhibitory effect during this period was partially reversible. As this reversibility was underlined only during the stationary phase, this suggested that this action could be situated upstream in a terpenoid non-specific pathway. 2,4-D feeding showed that inhibition is weaker and weaker as the alkaloid accumulation period proceeds. Auxin action during this period could take place downstream in specific alkaloid pathways. The lower alkaloid accumulation obtained after loganic acid feeding compared to that obtained with secologanin and loganin could indicate that loganic acid methylation should be one of the 2,4-D target(s).
Asunto(s)
Ácido 2,4-Diclorofenoxiacético/metabolismo , Iridoides , Plantas Medicinales/metabolismo , Alcaloides de Triptamina Secologanina , Alcaloides de la Vinca/metabolismo , Células Cultivadas , Glucósidos/farmacología , Glucósidos Iridoides , Plantas Medicinales/citología , Piranos/farmacología , Yohimbina/análogos & derivados , Yohimbina/metabolismoRESUMEN
The effects of cytokinins on the different branches of the indole alkaloid pathway were investigated in Catharanthus roseus cell cultures. Addition of zeatin to a 2,4-dichlorophenoxyacetic acid-containing medium decreased tryptamine levels and increased the bioconversion of secologanin to ajmalicine. Zeatin also enhanced the geraniol-10 hydroxylase activities and modified the indole alkaloid pattern. The results are discussed in the light of previous works showing that cytokinins have a positive effect on indole alkaloid accumulation in some lines of C. roseus.
RESUMEN
Cytokinins were found to stimulate the alkaloid synthesis induced by removing auxin from the medium of a cell line of Catharanthus roseus. Diluting the mineral salts of the culture medium decreased the alkaloid production but increased the "sensitivity" of the cells. Addition of high levels of Ca(2+), Mg(2+) or Sr(2+) to B5 media in which the mineral salts were diluted to 5-40%, increased the alkaloid production. The latter effect is related only partially to enhanced osmotic potential.
RESUMEN
Three different strains of CATHARANTHUS ROSEUS cells were compared during one subculture with regard to tryptophan, tryptamine, ajmalicine, serpentine contents and tryptophane decarboxylase (TDC) (4) and Strictosidine synthase activities. The strains differed greatly in their accumulation of tryptamine and alkaloid. The TDC of all three strains showed the highest activity during the growth phase and declined sharply at the end of this phase. On the contrary, strictosidine synthase activity was the lowest during the growth phase and increased distinctly at the same time when the alkaloids were accumulating. By comparing the three strains with each other, no correlation was observed between the values of enzymatic activities and the contents of accumulated alkaloids.
RESUMEN
Catharanthus roseus cells were cultured in three types of media. These media were: a low sucrose subculture medium and two high sucrose media, each of which differed in their mineral and hormonal contents. The kinetics of tryptophan decarboxylase activity and the accumulations of tryptophan, tryptamine, ajmalicine and serpentine were different in each series but no correlation between maximum enzyme activity and alkaloid contents was observed. Ajmalicine and serpentine productions were unaffected by addition of Trp to the media, whereas addition of secologanin enhanced alkaloid production. The results seem to imply that the terpenoid pathway is the limiting factor in alkaloid production in C. roseus cells.