Polysaccharide-water interactions: NMR and DVS data

The data provided here relate to the research paper "Assessing the complementarity of TD-NMR, solid-state NMR and Dynamic Vapor Sorption in the characterization of polysaccharide-water interactions". The original data from TD-NMR, ss-NMR and DVS is provided in .dps, topspin and .xls formats respectively, allowing other authors to repeat our processing protocols using different parameters. We also include results obtained by varying the signal treatments. The analysis of these multimodal data have highlighted a variation in polysaccharide-water interactions depending on the type of assembly. These datasets are very useful for discriminating between water bound to polysaccharides and water absorbed or adsorbed into polysaccharide network, a key element in understanding interactions in these assemblies and an essential approach for developing tailor-made polysaccharides-based products.

Assessing the complementarity of time domain NMR, solid-state NMR and dynamic vapor sorption in the characterization of polysaccharide-water interactions

Characterizing the hygroscopic behavior of macromolecular assemblies is crucial for understanding biological processes as well as to develop tailor-made polysaccharides-based products. In this work, assemblies consisting of nanocelluloses (CNC or CNF) and/or glucomannan in different ratio were studied at different water activity levels, using a multi-analytical approach that combined Dynamic Vapor Sorption (DVS), Time-Domain Nuclear Magnetic Resonance (TD-NMR) and solid-state NMR (ss-NMR). The water retention capacity of the films, as a function of their composition, showed that an enrichment in konjac glucomannan in association with cellulose increased the water absorption capacity but decreased the water retention capacity. In addition, the combination of CNC and glucomannan appears to reduce the water absorption capacity of each polymer. Correlating the findings from the various methods allowed us to propose the use of TD-NMR data for predicting the water retention capacity. These results, summarized in a schematic representation, offer new insights into the organization of water molecules in polysaccharide assemblies in various humidity conditions.

The BUMPy road of peritoneal metastases in ovarian cancer

Ovarian cancer is the most common cause of death due to gynecologic malignancies, with more than 70% of patients presenting with advanced stage disease at the time of diagnosis. The extent and distribution of tumor guide primary treatment selection and clinical management. While primary cytoreductive surgery with complete tumor resection improves survival, patients with extensive peritoneal disease may benefit from neoadjuvant chemotherapy first to reduce tumor burden followed by interval cytoreductive surgery. Imaging plays an essential role in triaging patients including selecting patients who may benefit from neoadjuvant chemotherapy before cytoreductive surgery. Interestingly, there are no universally established criteria to predict resectability and local practices depend on local guidelines and surgeon preferences. Nevertheless, certain anatomical tumor locations are known to be difficult to resect and are associated with suboptimal cytoreduction or require special surgical considerations. This review discusses the recent advances in the initial management of patients with ovarian cancer, a practical approach to the assessment and communication of peritoneal metastases locations on CT and MRI. It also explores recent advances in genomics profiling and radiomics that may influence the initial management of these patients.

The role of CT, PET-CT, and MRI in ovarian cancer

New treatment developments in ovarian cancer have led to a renewed interest in staging advanced ovarian cancer. The treatment of females with ovarian cancer patients has a strong multidisciplinary character with an essential role for the radiologist. This review aims to provide an overview of the current position of CT, positron emission tomography-CT, and MRI in ovarian cancer and how imaging can be used to guide multidisciplinary team discussions.

Central radiology assessment of the randomized phase III open-label OVHIPEC-1 trial in ovarian cancer

Introduction

Hyperthermic intraperitoneal chemotherapy (HIPEC) improved investigator-assessed recurrence-free survival and overall survival in patients with stage III ovarian cancer in the phase III OVHIPEC-1 trial. We analyzed whether an open-label design affected the results of the trial by central blinded assessment of recurrence-free survival, and tested whether HIPEC specifically targets the peritoneal surface by analyzing the site of disease recurrence.

Methods

OVHIPEC-1 was an open-label, multicenter, phase III trial that randomized 245 patients after three cycles of neoadjuvant chemotherapy to interval cytoreduction with or without HIPEC using cisplatin (100 mg/m2). Patients received three additional cycles of chemotherapy after surgery. Computed tomography (CT) scans and serum cancer antigen 125 (CA125) measurements were performed during chemotherapy, and during follow-up. Two expert radiologists reviewed all available CT scans. They were blinded for treatment allocation and clinical outcome. Central revision included Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 measurements and peritoneal cancer index scorings at baseline, during treatment, and during follow-up. Time to centrally-revised recurrence was compared between study arms using Cox proportional hazard models. Subdistribution models compared time to peritoneal recurrence between arms, accounting for competing risks.

Results

CT scans for central revision were available for 231 patients (94%) during neoadjuvant treatment and 212 patients (87%) during follow-up. Centrally-assessed median recurrence-free survival was 9.9 months in the surgery group and 13.2 months in the surgery+HIPEC group (HR for disease recurrence or death 0.72, 95% CI 0.55 to 0.94; p=0.015). The improved recurrence-free survival and overall survival associated with HIPEC were irrespective of response to neoadjuvant chemotherapy and baseline peritoneal cancer index. Cumulative incidence of peritoneal recurrence was lower after surgery+HIPEC, but there was no difference in extraperitoneal recurrences.

Conclusion

Centrally-assessed recurrence-free survival analysis confirms the benefit of adding HIPEC to interval cytoreductive surgery in patients with stage III ovarian cancer, with fewer peritoneal recurrences. These results rule out radiological bias caused by the open-label nature of the study.

Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy versus palliative systemic chemotherapy in stomach cancer patients with peritoneal dissemination, the study protocol of a multicentre randomised controlled trial (PERISCOPE II)

BACKGROUND

At present, palliative systemic chemotherapy is the standard treatment in the Netherlands for gastric cancer patients with peritoneal dissemination. In contrast to lymphatic and haematogenous dissemination, peritoneal dissemination may be regarded as locoregional spread of disease. Administering cytotoxic drugs directly into the peritoneal cavity has an advantage over systemic chemotherapy since high concentrations can be delivered directly into the peritoneal cavity with limited systemic toxicity. The combination of a radical gastrectomy with cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) has shown promising results in patients with gastric cancer in Asia. However, the results obtained in Asian patients cannot be extrapolated to Western patients. The aim of this study is to compare the overall survival between patients with gastric cancer with limited peritoneal dissemination and/or tumour positive peritoneal cytology treated with palliative systemic chemotherapy, and those treated with gastrectomy, CRS and HIPEC after neoadjuvant systemic chemotherapy.

METHODS

In this multicentre randomised controlled two-armed phase III trial, 106 patients will be randomised (1:1) between palliative systemic chemotherapy only (standard treatment) and gastrectomy, CRS and HIPEC (experimental treatment) after 3-4 cycles of systemic chemotherapy.Patients with gastric cancer are eligible for inclusion if (1) the primary cT3-cT4 gastric tumour including regional lymph nodes is considered to be resectable, (2) limited peritoneal dissemination (Peritoneal Cancer Index < 7) and/or tumour positive peritoneal cytology are confirmed by laparoscopy or laparotomy, and (3) systemic chemotherapy was given (prior to inclusion) without disease progression.

DISCUSSION

The PERISCOPE II study will determine whether gastric cancer patients with limited peritoneal dissemination and/or tumour positive peritoneal cytology treated with systemic chemotherapy, gastrectomy, CRS and HIPEC have a survival benefit over patients treated with palliative systemic chemotherapy only.

TRIAL REGISTRATION

clinicaltrials.gov NCT03348150 ; registration date November 2017; first enrolment November 2017; expected end date December 2022; trial status: Ongoing.

The Psychometric Properties of the French Version of the Trait Emotional Intelligence Questionnaire–Child Short Form

The psychometric properties of the French version of the Trait Emotional Intelligence Questionnaire–Child Short Form (TEIQue-CSF) were investigated in a sample of 556 children 9 to 13 years of age. The internal consistency and temporal stability were satisfactory. A significant difference for gender, but not for age, was observed. With regard to the factor structure, the best fit was found for a two-factor solution, emotion control and socioemotionality. Regarding convergent validity, positive correlations were found with the total and all except one-factor scores of the Emotion Awareness Questionnaire score (EAQ30). Evidences of concurrent validity were demonstrated, with negative correlations with State-Trait Anxiety Inventory for Children (STAIC) and childhood anxiety sensitivity index (CASI). Results also showed a positive correlation with Children’s Social Desirability Scale (CSD). In conclusion, these findings provide additional support for the use of the TEIQue-CSF for researchers and practitioners who want to assess emotion-related constructs in children.

Management and follow-up of gallbladder polyps : Joint guidelines between the European Society of Gastrointestinal and Abdominal Radiology (ESGAR), European Association for Endoscopic Surgery and other Interventional Techniques (EAES), International Society of Digestive Surgery - European Federation (EFISDS) and European Society of Gastrointestinal Endoscopy (ESGE)

Objectives

The management of incidentally detected gallbladder polyps on radiological examinations is contentious. The incidental radiological finding of a gallbladder polyp can therefore be problematic for the radiologist and the clinician who referred the patient for the radiological examination. To address this a joint guideline was created by the European Society of Gastrointestinal and Abdominal Radiology (ESGAR), European Association for Endoscopic Surgery and other Interventional Techniques (EAES), International Society of Digestive Surgery – European Federation (EFISDS) and European Society of Gastrointestinal Endoscopy (ESGE).

Methods

A targeted literature search was performed and consensus guidelines were created using a series of Delphi questionnaires and a seven-point Likert scale.

Results

A total of three Delphi rounds were performed. Consensus regarding which patients should have cholecystectomy, which patients should have ultrasound follow-up and the nature and duration of that follow-up was established. The full recommendations as well as a summary algorithm are provided.

Conclusions

These expert consensus recommendations can be used as guidance when a gallbladder polyp is encountered in clinical practice.

Key Points

• Management of gallbladder polyps is contentious

• Cholecystectomy is recommended for gallbladder polyps >10 mm

• Management of polyps <10 mm depends on patient and polyp characteristics

• Further research is required to determine optimal management of gallbladder polyps

Sécurité d’emploi, tolérance et efficacité du palmitate de palipéridone à doses flexibles chez des patients schizophrènes hospitalisés pour une décompensation psychotique

Objectif

Explorer sécurité d’emploi, tolérance et efficacité du palmitate de palipéridone (PP) à doses flexibles chez des patients adultes schizophrènes hospitalisés pour une décompensation.

Méthodes

Étude internationale, prospective, en ouvert, non-interventionnelle de 6 semaines.

Évaluation

Échelles BPRS (Brief Psychiatric Rating Scale), CGI-S (Clinical Global Impression-Severity), PSP (Personal and Social Performance Scale), questionnaire de satisfaction sur le traitement (MSQ-Medication Satisfaction Questionnaire), ESRS (Extrapyramidal Symptom Rating Scale) et évènements indésirables sous traitement (EIST), entre début d’étude (baseline) et dernière observation rapportée.

Résultats

Trois cent soixante-sept patients analysés (65,9% hommes, âge moyen (± écart-type) 39,8 ± 12,1 ans, 85,8% schizophrénie paranoïde). Au total, 91,6% des patients ont terminé l’étude de 6 semaines. Le délai moyen entre l’admission à l’hôpital et l’initiation du PP était de 9,4 ± 7,7 jours. Le score initial BPRS (50,2 ± 13,6) s’est amélioré de–6,5 ± 8,6 au jour 8 et de–19,3 ± 12,6 à la fin de l’étude (IC 95% = –20,7;–18,0; deux critères avec p < 0,0001). En fin d’étude, 93,6% des patients étaient évalués comme améliorés sur l’échelle CGI-S. Le score de fonctionnement PSP s’est amélioré de 49,4 ± 14,7 à baseline à 14,3 ± 12,4 en fin d’étude (IC 95% = 12,9; 15,8, p < 0,0001). Le score ESRS moyen a diminué de manière significative de 3,7 ± 5,9 (baseline) à 2,0 ± 4,7 en fin d’étude (p < 0,0001). Le pourcentage de patients très ou extrêmement satisfaits par leur traitement antipsychotique est passé de 6,0% à baseline (traitement précédent) à 46,1% en fin d’étude (PP). EIST rapportés chez ≥ 2% des patients: tremblements (2,5%) et schizophrénie (2,2%).

Conclusions

Ces données chez des patients schizophrènes hospitalisés pour décompensation confirment les résultats d’études contrôlées randomisées montrant que le PP à doses flexibles est bien toléré, induit une réponse au traitement rapide et cliniquement significative et une amélioration du fonctionnement. Traduction de l’abstract résumé présenté au congrès EPA 2015 (European Congress of Psychiatry – Vienna, Austria, 28–31 March 2015).

Solid-state graphene formation via a nickel carbide intermediate phase

Direct formation of graphene with a controlled number of graphitic layers on dielectric surfaces is achieved with an in-depth understanding of the solid-state growth mechanism.

Psychological, social and school implications of asthma: a comparison of Belgian French-speaking children having asthma with healthy children

The present study aimed to explore the psychosocial implications of asthma among Belgian French-speaking children. Ninety-nine parents of children having asthma (Mage=11.40, SD=2.35) and 102 parents of children without asthma (Mage=11.25, SD=.81) participated in the study. Parents filled in the Child Behaviour Checklist and a demographic questionnaire. Results showed that children having asthma were assessed by their parents as having more internalizing, social and attention problems and as having less competence in doing activities (e.g., sports, hobbies, jobs) than their healthy peers. Significant differences also appeared between genders for attention problems, anxiety/depression, activities, social and school competences, indicating that boys were more vulnerable to psychological and social difficulties than girls but they had better school competences than girls. Finally, results showed no difference for psychological, social, and school adjustment between children who controlled and partly controlled their asthma. These findings emphasize the importance of screening children who would be at risk for having psychosocial problems and developing multidisciplinary interventions for children with asthma and for their families.

Tolerability and treatment response in patients with recently diagnosed vs. chronic schizophrenia treated with paliperidone ER

Objective

To explore tolerability and treatment response in adult patients with recently diagnosed (≤5 years) and chronic (>5 years) schizophrenia treated with flexible doses of paliperidone ER.

Methods

International prospective open-label 6-month study. Endpoints were the Positive and Negative Syndrome Scale (PANSS), patient functioning and treatment-emergent adverse events (TEAEs).

Results

Of 713 recently diagnosed patients, most were male (60.9%), mean age was 33.6 ± 11.2 years and mean time since diagnosis was 2.3 ± 1.7 years. Chronic patients (n = 1003) were predominantly male (59.2%) with a mean age of 43.8 ± 11.4 and mean time since diagnosis of 15.6 ± 9.2 years. 70.4% and 71.7% of patients completed the study, respectively. Mean mode doses of paliperidone ER were similar between recently diagnosed and chronic patients (7.0 ± 2.9 mg/day and 7.2 ± 2.9 mg/day). 63.1% of recently diagnosed and 60.8% of chronic patients switching due to lack of efficacy with their previous antipsychotic had a ≥20% improvement in PANSS total score at endpoint, and improvement with other switching reasons was consistently numerically higher in recently diagnosed patients. The rate of patients with mild or no functional impairment increased from 17.7% to 39.8% in recently diagnosed and from 14.4% to 32.9% in chronic patients. TEAEs reported in ≥5% were insomnia (10.7% and 8.1%), anxiety (8.6% and 6.0%) and somnolence (5.8% and 3.4%), respectively.

Conclusion

These data suggest that both recently diagnosed and chronic patients previously unsuccessfully treated with other oral antipsychotics may benefit from paliperidone ER, with a tendency for recently diagnosed patients showing some higher treatment response in psychotic symptoms and patient functioning.

Functioning in patients with recently diagnosed vs. chronic schizophrenia treated with paliperidone ER

Objective

To explore functioning in adult patients with recently diagnosed (< 5 years) and more chronic (> 5 years) schizophrenia treated with flexible doses of paliperidone ER.

Methods

International prospective open-label 6-month study. Endpoints were the Positive and Negative Syndrome Scale (PANSS), patient functioning (Personal and Social Performance Scale; PSP) and treatment-emergent adverse events (TEAEs).

Results

Of 713 recently diagnosed patients, most were male (60.9%), mean age was 33.6 ± 11.2 years and mean time since diagnosis was 2.3 ± 1.7 years. Chronic patients (n = 1003) were predominantly male (59.2%) with a mean age of 43.8 ± 11.4 and mean time since diagnosis of 15.6 ± 9.2 years. Mean mode doses of paliperidone ER were similar between recently diagnosed and chronic patients (7.0 ± 2.9 mg/day and 7.2 ± 2.9 mg/day). At endpoint PANSS total scores were improved by 13.7 and 12.9 points, respectively, in recently diagnosed and chronic patients. The rate of patients with mild or less functional impairment increased from 17.7% to 39.8% in recently diagnosed and from 14.4% to 32.9% in chronic patients. Major functional improvements were observed for socially useful activities and personal and social relationships. TEAEs reported in >5% of recently diagnosed or chronic patients were insomnia (10.7% and 8.1%), anxiety (8.6% and 6.0%) and somnolence (5.8% and 3.4%), respectively.

Conclusion

These data suggest that both recently diagnosed and chronic patients previously unsuccessfully treated with other oral antipsychotics may benefit from paliperidone ER, with a tendency for recently diagnosed patients showing some higher treatment response in psychotic symptoms and patient functioning, particularly in socially useful activities and personal and social relationships.

Topiramate reduces headache days in chronic migraine: a randomized, double-blind, placebo-controlled study

The aim of this study was to evaluate the efficacy and tolerability of topiramate for the prevention of chronic migraine in a randomized, double-blind, placebo-controlled trial. Chronic migraine is a common form of disabling headache presenting in headache subspecialty practice. Preventive treatments are essential for chronic migraine management, although there are few or no controlled empirical trial data on their use in this patient population. Topiramate is approved for the prophylaxis of migraine headache in adults. Patients (18-65 years) who experienced chronic migraine (defined as > or =15 monthly migraine days) for > or =3 months prior to trial entry and had > or =12 migraine days during the 4-week (28-day) baseline phase were randomized to topiramate or placebo for a 16-week, double-blind trial. Topiramate was titrated (25 mg weekly) to a target dose of 100 mg/day, allowing dosing flexibility from 50 to 200 mg/day, according to patient need. Existing migraine preventive treatments, except for antiepileptic drugs, were continued throughout the trial. The primary efficacy measure was the change in number of migraine days from the 28-day baseline phase to the last 28 days of the double-blind phase in the intent-to-treat population, which consisted of all patients who received at least one dose of study medication and had one outcome assessment during the double-blind phase. Health-related quality of life was evaluated with the Migraine Specific Quality of Life Questionnaire (MSQ, Version 2.1), the Headache Impact Test (HIT-6) and the Migraine Disability Assessment (MIDAS) questionnaires, and tolerability was assessed by adverse event (AE) reports and early trial discontinuations. Eighty-two patients were screened. Thirty-two patients in the intent-to-treat population (mean age 46 years; 75% female) received topiramate (mean modal dose +/- SD = 100 +/- 17 mg/day) and 27 patients received placebo. Mean (+/-SD) baseline number of migraine days per 4 weeks was 15.5 +/- 4.6 in the topiramate group and 16.4 +/- 4.4 in the placebo group. Most patients (78%) met the definition for acute medication overuse at baseline. The mean duration of treatment was 100 and 92 days for topiramate- and placebo-treated patients, respectively. Study completion rates for topiramate- and placebo-treated patients were 75% and 52%, respectively. Topiramate significantly reduced the mean number of monthly migraine days (+/-SD) by 3.5 +/- 6.3, compared with placebo (-0.2 +/- 4.7, P < 0.05). No significant intergroup differences were found for MSQ and HIT-6. MIDAS showed improvement with the topiramate treatment group (P = 0.042 vs. placebo). Treatment emergent adverse events were reported by 75% of topiramate-treated patients (37%, placebo). The most common AEs, paraesthesia, nausea, dizziness, dyspepsia, fatigue, anorexia and disturbance in attention, were reported by 53%, 9%, 6%, 6%, 6%, 6% and 6% of topiramate-treated patients, respectively, vs. 7%, 0%, 0%, 0%, 0%, 4% and 4% of placebo-treated patients. This randomized, double-blind, placebo-controlled trial demonstrates that topiramate is effective and reasonably well tolerated when used for the preventive treatment of chronic migraine, even in the presence of medication overuse.

Experience with topiramate monotherapy in elderly patients with recent-onset epilepsy

OBJECTIVES

To evaluate the effect of topiramate in elderly patients with onset of epilepsy after the age of 60, treatment-naive or non-responding to an initial antiepileptic drug.

METHODS

Analysis of patients with epilepsy diagnosed in the preceding 5 years, aged>/=65 years (n=43), enrolled in a larger open-label trial (n=692). After titration to topiramate 100 mg/day over 4 weeks, the dose was adjusted according to individual response (maximum 400 mg/day). Patients were followed up for at least 7 months.

RESULTS

After 7 months, 79% of patients remained in the study. Seizure frequency decreased significantly vs baseline (P<0.001); >/=50% reduction in seizure frequency was achieved in 87% of patients, 64% remained seizure-free. Both previously treated and naive patients responded. Fourteen per cent dropped out because of insufficient tolerability. No unexpected or unusual adverse events were observed.

CONCLUSIONS

The results indicate that elderly patients respond well to topiramate monotherapy. The high patient retention rate reflects a favourable tolerability profile in this population.

Structural analysis of Gigartina pistillata carrageenans (Gigartinaceae, Rhodophyta)

The chemical structure of carrageenans produced by the gametophytic and tetrasporophytic life cycle phases of Gigartina pistillata has been determined by permethylation analysis, IR and 13C NMR spectroscopies. The chemistry of the galactans varies according to the biological phases of the plant, the gametophytic alga produces heterogeneous kappa-iota type carrageenan containing minor amounts of nu-carrabiose. The tetrasporophytic alga synthesizes a complex sulfated galactan composed of lambda-, xi-, pi-carrabioses and sulfated carrabioses containing 3-linked galactopyranose 2,6-disulfate.

In vitro anti-HIV activity of sulfated cell-wall polysaccharides from gametic, carposporic and tetrasporic stages of the Mediterranean red alga Asparagopsis armata

The gametic, carposporic and tetrasporic reproductive stages from the Mediterranean red alga Asparagopsis armata contain peculiar sulfated galactans with galactose:3,6-anhydrogalactose:sulfates molar ratio of 1:0.01:1.23, 1:0.04:0.47 and 1:0.01:1.13, respectively. These water-soluble polysaccharides were studied for their in vitro activity against the human immunodeficiency virus (HIV-1). Gametic and tetrasporic galactans inhibit HIV replication at 10 and 8 micrograms/ml, respectively, as measured by HIV-induced syncitium formation as well as reverse transcriptase activity in cell-free culture supernatant. The carposporic polysaccharide is ineffective, even at 100 micrograms/ml. The maximal antiviral effect involves the presence of the polysaccharides after or during infection but not before infection. This time of action suggests an inhibition of an early step of HIV infection.

Non-starch polysaccharides extracted from seaweed can modulate intestinal absorption of glucose and insulin response in the pig

We have investigated the possible effects of algal polysaccharides on postprandial blood glucose and insulin responses in an animal model, the pig. Three seaweed fibres of different viscosities, extracted from Palmaria palmata (PP), Eucheuma cottonii (EC), or Laminaria digitata (LD), were compared to purified cellulose (CEL). Blood glucose and plasma insulin levels were monitored and intestinal absorption quantified for 8 h following a high carbohydrate test-meal supplemented with 5% fibre. Digestive contents were also sampled, 5 h postprandial. As compared to CEL, PP had no effect on glucose and insulin responses. The latter decreased with EC, but glucose absorption balance was not modified. LD addition resulted in a dramatically reduced glucose absorption balance, accompanied by a higher amount of starch left in the small intestine. Among polysaccharides tested, only the highly viscous alginates could affect intestinal absorption of glucose and insulin response.

Biological properties of ulvan, a new source of green seaweed sulfated polysaccharides, on cultured normal and cancerous colonic epithelial cells

Ulvans (from Ulva lactuca) constitute a dietary fiber structurally similar to the mammalian glycosaminoglycans but with unexplored biological or cytotoxic activities. From native low-viscosity preparations containing 33.5 molar % and 18.4 molar % of sulfate residues and uronic acid residues, respectively, we derived desulfated, reduced and desulfated-reduced polysaccharides with respectively 5.2, 2.9, and 4.5-4.9 molar % of sulfate residues and uronic acid residues. The effects of these preparations were examined on the adhesion, proliferation and differentiation of normal or tumoral colonic epithelial cells cultured in conventional (0.3-0.8 x 10(6) cells/ml) or rotating bioreactor (3-8 x 10(6) cells/ml) culture conditions. In conventional culture conditions, ulvan modified the adhesion phase and the proliferation of normal colonic cells and undifferentiated HT-29 cells according to their molecular weights and to the relative molar proportion of sulfate residues. From the native polysaccharides, we have screened sulfated ulvans (MW < 5,000) which inhibited the Caco-2 cell proliferation/differentiation program by inducing a low cell reactivity to Ulex europeaus-1 lectins in defined (p < 0.001) or serum-supplemented media (p < 0.01) but were inactive on normal colonocytes. In conclusion, this dietary fiber could be a source of oligosaccharides with a bioactivity, a cytotoxicity or a cytostaticity targeted to normal or cancerous epithelial cells.

NMR spectroscopic characterisation of oligosaccharides from two Ulva rigida ulvan samples (Ulvales, Chlorophyta) degraded by a lyase

The chemical structure and the sequence of repeating units in ulvans of similar compositions from two different Ulva rigida samples collected in the Canary Islands and in Brittany were studied after ulvan-lyase degradation and NMR spectroscopic analysis of the reaction products. Both ulvans were composed of ulvanobiuronic acid 3-sulfate type A [-->4)-beta-D-GlcA-(1-->4)-alpha-L-Rha 3-sulfate-(1-->] (symbolised as A3s) and contained disaccharides composed of [-->4)-beta-D-Xyl-(1-->4)-alpha-L-Rha 3-sulfate-(1-->] and [-->4)-beta-D-Xyl 2-sulfate-(1-->4)-alpha-L-Rha 3-sulfate], respectively referred to as ulvanobiose 3-sulfate (U3s) and ulvanobiose 2',3-disulfate (U2's,3s). In the Canary Islands sample, these U3s and U2's,3s occurred dispersed among A3s sequences and as short blocks of two or three units. In contrast, in the Brittany samples, these units were dispersed among A3s structures and next to A3s units branched at O-2 of alpha-L-Rha 3-sulfate by a terminal beta-D-GlcA and symbolised as A2g,3s. However, more complex structures are likely to occur in the enzyme resistant fraction remaining from this ulvan. An average structure sequence of these two ulvans was proposed. The transposition of the 13C NMR data of the new identified structures to the parent polysaccharides was not possible, probably due to the different sequence distributions affecting the carbons chemical shifts.

Purification and determination of the action pattern of Haliotis tuberculata laminarinase

The major laminarinase activity (EC 3.2.1.39) from the gastropodean marine mollusc Haliotis tuberculata was purified to homogeneity by cation exchange chromatography and its action pattern was investigated by HPAEC-PAD analysis of the degradation of various laminarin samples. It consists of a 60 kDa protein capable of depolymerizing the unbranched portions of the beta-(1-->3), beta-(1-->6)-glucan, down to laminaritriose. The enzyme operates via a molecular mechanism retaining the anomeric configuration. As the purified protein does not cleave the beta-(1-->6) linkages, it can be used for the structural analysis of laminarins.

Isolation and structural characterisation of rhamnogalacturonan oligomers generated by controlled acid hydrolysis of sugar-beet pulp

Controlled acid hydrolysis was applied to a deesterified beet pulp and the resulting soluble fraction was fractionated on a Biorad AG 1X8 column eluted by ammonium acetate pH 6 from 0.05 to 2 M. Eight retained fractions were obtained, containing almost exclusively GalA and Rha. Three types of oligomers could be identified: homogalacturonans, of which mono-,di- and tri-GalA were isolated as individual components, and two series of rhamnogalacturonan (RG) oligomers. One RG oligomer, isolated after ion-exchange chromatography, was identified as alpha-D-GalAp-(1-->2)-alpha-L-Rhap-(1-->4)-alpha-D-GalA p-(1-->2)-L-Rhap. The major peak contained oligomers of dp 6 to more than 20, of which dp 6 to 16 could be isolated on Bio-Gel P-6 + P-4. NMR of the oligomers of dp 6 to 10 showed the following structure: alpha-D-GalAp-(1[-->2)-alpha-L-Rhap-(1-->4)-alpha-D-GalA p-(1]n-->2)-L-Rhap. A second, quantitatively minor, series of RG oligomers eluted at higher ionic strength. These oligomers, which could be hydrolysed by RG-hydrolase and RG-lyase, were based on the alternating RG structure. Their non-reducing end was GalA, susceptible to hydrolysis by RG-galacturonohydrolase, and their reducing end might have more than one consecutive GalA.

Fine chemical structure analysis of oligosaccharides produced by an ulvan-lyase degradation of the water-soluble cell-wall polysaccharides from Ulva sp, (Ulvales, Chlorophyta)

A marine bacterium degrading the water-soluble cell wall polysaccharides from Ulva sp. (ulvan) has been isolated. The good correlation between ulvan degradation monitored by reducing-power, UV absorbance and viscosimetry, indicated that the crude enzymatic extract contains essentially an endo-ulvan lyase activity. This activity was rapidly inhibited by the reaction products which consisted of a series of ulvanobiouronic acid A 3-sulfate [-->4)-beta-D-GlcpA-(1-->4)-alpha-L-Rhap 3-sulfate-(1-->]n with 4-deoxy-L-threo-hex-4-enopyranosiduronic acid at the non-reducing end. Other deviant repeating structures with beta-D-Xylp or alpha-IdopA replacing beta-D-GlcpA in the repeating ulvanobiouronic acid disaccharide and the presence of two consecutive (1-->4) linked beta-D-Glc pA demonstrated the great variability and complexity of ulvan chemical structure.

Fermentation of green alga sea-lettuce (Ulva sp) and metabolism of its sulphate by human colonic microbiota in a semi-continuous culture system

The green alga, sea-lettuce (Ulva sp), could be considered as a new source of dietary fibre. Ulva, however, contains high levels of sulphate, part of which is chemically bound in soluble polymers (ulvan). The purpose of this study was to assess the fermentation characteristics and sulphate metabolism of Ulva and ulvan by human faecal bacteria fermentation system using a semi-continuous fermenter. Ulva and ulvan were poorly fermented, even after adaptation of the microbiota. Only 16.6% and 8.9% of Ulva and ulvan organic matter, respectively, were recovered as short chain fatty acids. Nevertheless, 40% of the sulphate in Ulva was dissimilated to sulphide by sulphate-reducing bacteria. Supplementation of Ulva with more fermentable polysaccharides, such as algal xylan and resistant starch, though decreasing the ammonia production originating from Ulva protein degradation, did not significantly reduce the sulphide levels. It is postulated that unless crude Ulva is desulphated, its daily consumption at a level of 20 g of dry product could stimulate colonic microbial sulphate reduction, which may have detrimental effects for the host.

Physico-chemistry and cytotoxicity of ceramics: part I: characterization of ceramic powders

The morphology of Al2O3, ZrO2/Y2O3, AIN, B4C, BN, SiC, Si3N4, TiB2, TiC, TiN ceramic, graphite and diamond powders has been studied by scanning electron microscopy (SEM) and the specific area of each powder was determined with the BET method. X-ray diffraction (XRD) investigations have been carried out in order to evaluate the crystallinity and determine the constitutive phases. The chemical composition was assessed by classical chemical analyses and by X-ray microprobe; some powders were studied by the laser micro-Raman technique. Correlations have been established between all these results.

Cell-wall polysaccharides from the marine green alga Ulva "rigida" (Ulvales, Chlorophyta)--NMR analysis of ulvan oligosaccharides

In order to obtain information on sugar sequences in the water soluble polysaccharides from Ulva "rigida", oligosaccharides were purified by anion exchange and gel permeation chromatography from the partial acid hydrolysate of the native or desulfated ulvan. The chemical structure and sugar sequence of these oligomers were determined by 1H and 13C NMR spectroscopy to be alpha-L-rhamnosyl (1-->4) D-xylose, beta-D-glucuronosyluronic acid (1-->2)-alpha-L-rhamnosyl (1-->4) D-xylose, beta-D-glucuronosyluronic acid (1-->4) L-rhamnose 3 sulfate, beta-D-glucuronosyluronic acid (1-->4) [beta-D-glucuronosyluronic acid (1-->2)] L-rhamnose and beta-D-glucuronosyluronic acid (1-->4) [beta-D-glucuronosyluronic acid (1-->2)] alpha-L-rhamnosyl (1-->4) D-xylose. The sugar linkages and particularly the branching and the sulfate position were in total agreement with previous chemical results.