L'incidence annuelle du syndrome de Guillain-Barre est de 1,5/100000 habitants La mortalite actuelle est estimee a environ 5 % d'apres des essais therapeutiques recents, bien conduits Dix pour cent des malades gardent des sequelles motrices tres invalidantes un an apres le debut des premiers signes neurologiques La prise en charge de ces malades necessite des equipes entrainees, multidisciplinaires, pouvant pratiquer l'ensemble des therapeutiques specifiques La corticotherapie per os'ou par voie intraveineuse est inefficace Les echanges plasmatiques sont le premier traitement dont l'efficacite a ete demontree par rapport a un groupe controle Les indications sont maintenant mieux connues Les formes benignes (marche possible) beneficient de 2 echanges plasmatiques; 2 echanges supplementaires sont realises en cas d'aggravation Dans les formes intermediaires (marche impossible) et les formes severes (recours a la ventilation mecanique), 4 echanges plasmatiques sont conseilles Il n'est pas utile d'augmenter leur nombre dans les formes severes ou en cas d'absence d'amelioration De fortes doses d'immunoglobulines donnees par voie intraveineuse (lq IV) [0,4 g/kg/j pendant 5 jours] sont aussi efficaces que les echanges plasmatiques dans les formes intermediaires et severes Dans ces formes, le choix entre Ig IV et echanges plasmatiques depend des contre-indications respectives de ces traitements et de leur faisabilite Les travaux en cours ont comme objectif de mieux preciser les indications respectives des echanges plasmatiques et des lq IV dans des formes de gravite differente, leur morbidite comparee, la dose optimale des lq IV

[Guillain-Barré syndrome].

Polyphenols as antimicrobial agents

Chitin and its deacetylated derivative chitosan are natural polymers composed of randomly distributed � -(1-4)- linked D-glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit). Chitin is insoluble in aqueous media while chitosan is soluble in acidic conditions due to the free protonable amino groups present in the D-glucosamine units. Due to their natural origin, both chitin and chitosan can not be defined as a unique chemical structure but as a fam- ily of polymers which present a high variability in their chemical and physical properties. This variability is related not only to the origin of the samples but also to their method of preparation. Chitin and chitosan are used in fields as different as food, biomedicine and agriculture, among others. The success of chitin and chitosan in each of these specific applica- tions is directly related to deep research into their physicochemical properties. In recent years, several reviews covering different aspects of the applications of chitin and chitosan have been published. However, these reviews have not taken into account the key role of the physicochemical properties of chitin and chitosan in their possible applications. The aim of this review is to highlight the relationship between the physicochemical properties of the polymers and their behaviour. A functional characterization of chitin and chitosan regarding some biological properties and some specific applications (drug delivery, tissue engineering, functional food, food preservative, biocatalyst immobilization, wastewater treatment, molecular imprinting and metal nanocomposites) is presented. The molecular mechanism of the biological properties such as biocompatibility, mucoadhesion, permeation enhancing effect, anticholesterolemic, and antimicrobial has been up- dated.

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Functional Characterization of Chitin and Chitosan

Proanthocyanidins are oligomeric and polymeric end products of the flavonoid biosynthetic pathway. They are present in the fruits, bark, leaves and seeds of many plants, where they provide protection against predation. At the same time they give flavor and astringency to beverages such as wine, fruit juices and teas, and are increasingly recognized as having beneficial effects on human health. The presence of proanthocyanidins is also a major quality factor for forage crops. The past 2 years have seen important breakthroughs in our understanding of the biosynthesis of the building blocks of proanthocyanidins, the flavan-3-ols (+)-catechin and (-)-epicatechin. However, virtually nothing is known about the ways in which these units are assembled into the corresponding oligomers in vivo. Molecular genetic approaches are leading to an understanding of the regulatory genes that control proanthocyanidin biosynthesis, and this information, together with increased knowledge of the enzymes specific for the pathway, will facilitate the genetic engineering of plants for introduction of value-added nutraceutical and forage quality traits.

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Proanthocyanidins--a final frontier in flavonoid research?

Nematode Parasites of Vertebrates: Their Development and Transmission

In vitro tests and ethnopharmacological investigations: Wound healing as an example

Saffron (stigmata of Crocus sativus L.) has been used for medicinal purposes for millennia. Throughout history, uses against cancer and depressive mood can regularly be identified. These applications have also been in the focus of modern research. Promising and selective anti-cancer effects have been observed in vitro and in vivo, but not yet in clinical trials. Antidepressant effects were found in vivo and in clinical pilot studies. Saffron extracts thus have the potential to make a major contribution to rational phytotherapy.

Saffron in phytotherapy: pharmacology and clinical uses.

An ethnopharmacological survey and in vitro confirmation of ethnopharmacological use of medicinal plants used for wound healing in Bosomtwi-Atwima-Kwanwoma area, Ghana.

In Asian medicine the fruit of the okra plant, Abelmoschus esculentus (L.) Moench., is used as a mucilaginous food additive against gastric irritative and inflammative diseases. To find a rational basis for its use against these diseases, several crude and purified carbohydrate-containing fractions from immature okra fruits were isolated and analyzed, and their effects against Helicobacter pylori in an in situ adhesion model on sections of human gastric mucosa were determined. Pretreatment of the bacteria with a fresh juice preparation inhibited the bacterial adhesion almost completely. Lyophilization and reconstitution of an extract solution led to a reduction of this effect. A crude polysaccharide (RPS) isolated from the fresh juice by ethanolic precipitation showed strong inhibitory effects. Further fractionation of RPS revealed a purified, highly acidic subfraction (AF III) with high antiadhesive qualities. Carbohydrate analysis revealed the presence of rhamnogalacturonans with a considerable amount of glucuronic acid, whereas other inactive subfractions contained little glucuronic acid or were glucuronic acid-free. After heat denaturation of the fresh juice or protein precipitation with 5% TCA the antiadhesive activity of the fresh extract was reduced, indicating that besides polysaccharides, protein fractions also exhibited antiadhesive properties. SDS-PAGE analysis of the precipitate revealed several bands of glycosylated proteins between 25 and 37 kDa that were almost diminished in the nonactive supernatant. Preincubations of gastric tissue with any of the active fractions did not lead to reduced bacterial binding. The antiadhesive activity is therefore due to the blocking capacity of specific Helicobacter surface receptors that coordinate the interaction between host and bacterium. Neither of the active fractions showed inhibitory effects on bacterial growth in vitro. The antiadhesive qualities of okra were assumed to be due to a combination of glycoproteins and highly acidic sugar compounds making up a complex three-dimensional structure that is fully developed only in the fresh juice of the fruit.

Andreas Hensel

Papers

In vitro tests and ethnopharmacological investigations: Wound healing as an example

Saffron in phytotherapy: pharmacology and clinical uses.

An ethnopharmacological survey and in vitro confirmation of ethnopharmacological use of medicinal plants used for wound healing in Bosomtwi-Atwima-Kwanwoma area, Ghana.

Glycosylated compounds from okra inhibit adhesion of Helicobacter pylori to human gastric mucosa.

Aqueous extracts and polysaccharides from Liquorice roots (Glycyrrhiza glabra L.) inhibit adhesion of Helicobacter pylori to human gastric mucosa