Tuning the functional properties of lignocellulosic films by controlling the molecular and supramolecular structure of lignin.

This study investigated the relationships between lignin molecular and supramolecular structures and their functional properties within cellulose-based solid matrix, used as a model biodegradable polymer carrier. Two types of derivatives corresponding to distinct structuration levels were prepared from a single technical lignin sample (PB1000): phenol-enriched oligomer fractions and colloidal nanoparticles (CLP). The raw lignin and its derivatives were formulated with cellulose nanocrystals or nanofibrils to prepare films by chemical oxidation or pressure-assisted filtration. The films were tested for their water and lignin retention capacities, radical scavenging capacity (RSC) and antimicrobial properties. A structural investigation was performed by infrared, electron paramagnetic resonance spectroscopy and microscopy. The composite morphology and performance were controlled by both the composition and structuration level of lignin. Phenol-enriched oligomers were the compounds most likely to interact with cellulose, leading to the smoothest film surface. Their RSC in film was 4- to 6-fold higher than that of the other samples. The organization in CLP led to the lowest RSC but showed capacity to trap and stabilize phenoxy radicals. All films were effective against S. aureus (gram negative) whatever the lignin structure. The results show the possibility to tune the performances of these composites by exploiting lignin multi-scale structure.

[French clinical guidelines for prevention of perianaesthetic dental injuries: long text]. / Bris dentaires périanesthésiques: texte long.

INTRODUCTION: Dental injuries represent the most common claims against the anaesthesiologists. Dental lesions are frequent complications of orotracheal intubation and major causal factors are, firstly, preexisting poor dentition, and, secondly, difficult laryngoscopy and tracheal intubation. The aim of this work was to prioritize propositions for prevention in perianaesthetic dental injury and for care in case of dental trauma. METHOD: A GRADE consensus procedure consisting of three rounds was conducted. A purposively selected heterogeneous panel (n=15) of experts, comprising 10 practitioners in anesthesiology, one practitioner who is jurist and anaesthesiologist, two practitioners in maxillofacial surgery, and two practitioners in dentist surgery. In cases where the data did not appear conclusive, recommendations were based on the consensus opinion of the board members. The guidelines represent the best current evidence based on literature search and professional opinion. RESULTS: The entire panel completed all three rounds and 31 plus six propositions were written for adult and paediatric clinical practice in anaesthesiology, respectively. The experts highlight the interest of preoperative visit for minimizing dental injuries: the practitioner must identify risk factors for difficult intubation and ventilation, describe precisely patient's preoperative dental condition, including upper incisor most commonly involved teeth in dental trauma. Patients have to be informed by practitioner for risk dental injury and anaesthesiology staff must choose his anesthesia protocol before the induction of intubation narcosis, avoiding insufficient anaesthesia and lack of experience by the anaesthesiologist. The choice of accurate proceeding during laryngoscopy, tracheal intubation and extubation for example, can aid in the prevention of dental injury, reduce the number of claims and the cost of litigation process. DISCUSSION: These guidelines delineate an approach for the prevention of perianaesthetic dental trauma and for the immediate or urgent care in case of perianaesthetic dental injury.

Inhibition of chitin synthase by a series of 7-deoxycasuarine stereoisomers designed as constrained analogues of the potent inhibitor 6-deoxyhomoDMDP.

A series of polyhydroxy-pyrrolizidines were designed as constrained analogues of 6-deoxy-homoDMDP, a potent naturally occurring inhibitor of chitin synthase. Enzymatic evaluation revealed that 7-deoxycasuarine was the best inhibitor of the series (IC50 = 820 microM) displaying a noncompetitive inhibition pattern, whereas the other tested compounds had IC50 in the range 4.3-18.9 mM. This is the first report of pyrrolizidine-type iminosugars inhibiting a glycosyltransferase. In addition, the inhibitory potencies towards glycosidases of these synthetic casuarine analogues is also disclosed.

Inhibition of chitin synthase by a series of 7-deoxycasuarine stereoisomers designed as constrained analogues of the potent inhibitor 6-deoxyhomoDMDP.

A series of polyhydroxy-pyrrolizidines were designed as constrained analogues of 6-deoxyhomoDMDP, a potent naturally occurring inhibitor of chitin synthase. Enzymatic evaluation revealed that 7-deoxycasuarine was the best inhibitor of the series (IC50 = 820 microM) displaying a non-competitive inhibition pattern, whereas the other tested compounds had IC50 in the range 4.3-18.9 mM. This is the first report of pyrrolizidine-type iminosugars inhibiting a glycosyltransferase. In addition, the biological evaluation towards glycosidases of these synthetic casuarine analogues is also disclosed.

Apical microleakage of radiolabeled lysozyme over time in three techniques of root canal obturation.

The three methods of obturation assessed in this study were lateral condensation (80 teeth), Thermafil (40 teeth), and McSpadden (40 teeth). All teeth were prepared to the master apical file 30 and widened coronally by Gates Glidden burs before being randomly assigned to experimental groups to be filled by each technique; they were then sealed with nail polish, except for the apical 1 mm. Quantitative evaluation of apical microleakage for each technique was obtained after periods of 1 day, 7 days, 14 days, and 28 days of immersion in a lysozyme solution labeled with radioactive iodine by preparing horizontal sections of the teeth and measuring the level of radioactivity in each section using a gamma counter. Initial (1-day) leakage was least in the Thermafil group and was significantly different from the other techniques. Leakage was greatest in the laterally condensed samples. By the end of the study (28th day) values for lateral condensation were lowest, but were significantly different only for the McSpadden group. For all techniques leakage was most significant in the first 3 mm from the apex and was very low below this level so that all methods can be considered as giving a hermetic seal below 3 mm.

[Experimental evaluation of an electronic apical locating instrument: study of 100 clinical cases]. / Valeurs expérimentales d'un appareil électronique de localisation apicale: étude sur 100 cas cliniques.

A statistical study has been conducted in order to study the efficiency of an "R.C.M. apex locator" in endodontometry. The study is based on 97 electronic measurements in vivo, all samples being controlled in vitro by X-Ray examination after extraction of the teeth, the instrument remaining in the canal. Results showed that the "R.C.M. apex locator" allows a success rate of 85% length recorded being short of beyond the apex by 0.5 mm.

[Daily practice and pulp diseases]. / La pratique quotidienne et les pulpopathies.

Constructive or destructive processes of pulp tissue depend on many factors: anatomic topography, particular physiology, or intensity and duration of infectious, mechanical and chemical aggression. Also irritation of the pulpo-dentinal complex induce histologic and physiologic changes. The positive diagnosis of hyperemia, acute or chronic pulpitis, pulpal necrosis and acute or chronic apical abscess is performed by clinical investigations which allow a differential diagnosis with other dental or extra-dental diseases. These multiple steps lead to an adapted and appropriate treatment.

[Ocular manifestations of dental disease (apropos of one case)]. / Manifestations oculaires et affections dentaires (à propos d'une observation).

Dental infections are able to produce ocular diseases by direct metastatic reflex or allergic pathways. Generally, these diseases quickly heal after a symptomatic local treatment with antibiotics and anti-inflammatory medications associated to an etiologic therapy in order to eliminate the dental infection and the allergic hypersensitivity. The dental surgeon has a key position by promptly establishing a proper diagnosis and an efficient local treatment: the prognosis depends on these factors.