A reversed-phase high-performance liquid chromatographic method for the determination of alpha-tocopherol in plasma or erythrocytes with photodiode-array detection is described. Using this detector, ...information about the spectrum, absorption maxima and purity of the peak is obtained. Tocopherol was separated on a 5-microns Spherisorb ODS-2 column with methanol as element at a flow-rate of 1.0 ml/min. As little as 100 microliters of plasma or 150 microliters of erythrocytes can be used for accurate analysis with direct extraction without saponification. The speed, specificity, sensitivity and reproducibility of this technique make it particularly suitable for the routine determination of alpha-tocopherol in plasma or erythrocytes.
In pig to human discordant xenotransplantation there is evidence that hyperacute rejection (HAR) is mediated by the binding of natural xenoantibodies (NxAb) to endothelial xenoantigens with ...subsequent complement system activation.
1 Hence, prolonged graft survival using complement inhibitors such as cobra venom factor,
2 sCR1,
3 or transgenic animals expressing human complement regulatory proteins such as DAF
4 or CD59,
5 has been observed. Thus, complement plays a pivotal role in endothelial barrier disruption and in the development of HAR.
6
Ex vivo organ perfusion is accepted as a useful tool to study HAR in the pig to human discordant combination.
7 Most of the xenoperfusion experiments in this combination have been performed using pig hearts or pig livers; there is less experience in the functional evaluation of pig kidneys perfused with human blood. We designed this work in order to evaluate the functional and pathologic findings in pig kidneys perfused with complement-inactivated human blood.
Dans cette note, nous décrivons une méthode simple, permettant l'ultracentrifugation de particules virales planctoniques et leur observation en microscopie électronique à transmission. Une ...description de différents morphotypes de particules assimilables à des virus est faite à partir d'échantillons prélevés dans la couche euphotique d'un lac eutrophe (Aydat), au cours des périodes printanière et estivale. Ces particules présentent chacune une capside icosaédrique régulière à 6 faces et une queue, dont les dimensions sont similaires à celles des phages décrits en milieu marin. La diversité des formes et le nombre de virions (10 fois supérieur à celui des bactéries), permettent d'émettre l'hypothèse selon laquelle les virus interviennent de façon significative dans le contrôle des abondances des communautés bactériennes en milieu lacustre.
In this short communication, we describe a simple method to ultracentrifuge and concentrate planktonic virus-like particles, for their examination with a transmission electron microscope. A description of different morphotypes of particles clearly assimilable to viruses is made in plankton samples from the euphotic layer of a eutrophic lake (Lake Aydat), during its spring and summer development. The particles possess a tail and a 6-sided icosahedral capsid-head, with dimensions similar to those of phages already described in marine systems. The diversity of viral forms and their abundance (10 fold higher than that of bacteria) in Lake Aydat, suggests a significant role in controlling bacterial number in lakes.
In this short communication, we describe a simple method to ultracentrifuge and concentrate planktonic virus-like particles, for their examination with a transmission electron microscope. A ...description of different morphotypes of particles clearly assimilable to viruses is made in plankton samples from the euphotic layer of a eutrophic lake (Lake Aydat), during its spring and summer development. The particles possess a tail and a 6-sided icosahedral capsid-head, with dimensions similar to those of phages already described in marine systems. The diversity of viral forms and their abundance (10 fold higher than that of bacteria) in Lake Aydat, suggests a significant role in controlling bacterial number in lakes.
Asthmatics who sometimes experience respiratory arrest during an exacerbation are a particular concern. To date no adequate explanation exists for this phenomenon. Impaired perception of resistive ...loads is considered a factor in the development of hypercapnic respiratory failure, especially during exacerbation in patients with chronic obstructive pulmonary disease. We analyzed the perception of resistive loads in 10 asthmatics who had suffered two or more respiratory arrests during an acute exacerbation. A group of eight asthmatics (same mean age and basal bronchial obstruction) who had never developed respiratory arrest or acidosis during their exacerbations was also studied. No statistically significant differences were found between the two groups in the perception of resistive loads. This negative result seems to exclude a deficiency in the ability to detect resistive loads as a cause of respiratory arrest in asthmatic patients.
Une enquête menée à l'aide d'un questionnaire couvrant l'ensemble du territoire français ainsi que l'étude spécifique d'écosystèmes aquatiques de type lacs et réservoirs ont permis de montrer que les ...proliférations de cyanobactéries toxiques pouvaient a priori affecter n'importe quel plan d'eau de la France. Les genres rencontrés responsables de la production de toxines, le plus souvent hépatiques, sont Microcystis, Planktothrix, Anaboena et Cylindrospermopsis. Les efflorescences peuvent se produire tout au long de l'année car certaines espèces sont adaptées aux eaux froides et elles ne sont pas liées de manière univoque à un état eutrophe de l'écosystème. La production toxinique est la plus élevée lorsque les populations cyanobactériennes sont peu ou pas diversifiées et à la lumière de travaux récents, cette production serait favorisée, en ce qui concerne les microcystines, par un milieu riche en nitrate, pauvre en ammonium et fortement carencé en fer. La suite à donner à ce travail pourrait être la création d'un observatoire national des efflorescences toxiques
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