Search PubMed⌕ Search

Biomedical subjects

P Breton

Publications and source records attributed to P Breton.

At least 37 records · Page 2Linked to original sources
PubMed2004

[Postradiation dental extractions].

INTRODUCTION: Healing may fail after postradiation dental extractions, with a risk of followed osteoradionecrosis, and its dramatic prognosis. We propose a protocol for postradiation extractions. MATERIAL AND METHODS: From January 2000 to December 2001, 107 patients underwent 287 dental extractions after radiation therapy: 80.5% in mandibular jaw, average radiation dose 61.6 Gy, average time between radiation and extraction 6 years. Extractions were performed under general anesthesia, diazanalgesia or local anesthesia, and extraction wounds were sutured after insertion of a collagenic sealant impregnated with gentamicin. General antibiotic prophylaxy was given. RESULTS: Healing failed in only two cases. The first case involved early-stage osteoradionecrosis and the second a tumoral localization. The rate of post-extraction osteoradionecrosis was thus 0.35%. DISCUSSION: A strict protocol associating non-traumatic surgery and an alveolar sealant can considerably decrease the risk of osteoradionecrosis after dental extraction in radiated bone.

Administration, Topical↗
PubMed2004

[Focus on the effect of orthognathic surgery on condylar remodeling].

Condylar remodeling is a physiologic process that aims to adapt the structure of the temporo-mandibular joint (TMJ) to meet the functional demands. It is based on an interaction between the mechanical forces sustained by the TMJ and the adaptative capacities of the condyle. Orthognathic surgery can sometimes be responsible for an excessive physical stress to the articular surfaces. In these cases, normal functional condylar remodelling shifts to the process of progressive condylar resorption. Effect of orthognathic surgery on condylar remodeling is a poorly understood and controversial issue. It is however considered as an etiology of postoperative skeletal relapse following orthognathic surgery. Based on two case reports, etiopathogenic hypotheses of this process are discussed as well as predisposing factors to condylar resorption following orthognathic surgery.

Adaptation, Physiological↗
PubMed2003

Comparative efficacy of diazepam and avizafone against sarin-induced neuropathology and respiratory failure in guinea pigs: influence of atropine dose.

This investigation compared the efficacy of diazepam and the water-soluble prodiazepam-avizafone-in sarin poisoning therapy. Guinea pigs, pretreated with pyridostigmine 0.1 mg/kg, were intoxicated with 4LD(50) of sarin (s.c. route) and 1 min after intoxication treated by intramuscular injection of atropine (3 or 33.8 mg/kg), pralidoxime (32 mg/kg) and either diazepam (2 mg/kg) or avizafone (3.5 mg/kg). EEG and pneumo-physiological parameters were simultaneously recorded. When atropine was administered at a dose of 3 mg/kg, seizures were observed in 87.5% of the cases; if an anticonvulsant was added (diazepam (2 mg/kg) or avizafone (3.5 mg/kg)), seizure was prevented but respiratory disorders were observed. At 33.8 mg/kg, atropine markedly increased the seizure threshold and prevented early respiratory distress induced by sarin. When diazepam was administered together with atropine, seizures were not observed but 62.5% of the animals displayed respiratory difficulties. These symptoms were not observed when using avizafone. The pharmacokinetic data showed marked variation of the plasma levels of atropine and diazepam in different antidote combination groups, where groups receiving diazepam exhibited the lowest concentration of atropine in plasma. Taken together, the results indicate that avizafone is suitable in therapy against sarin when an anticonvulsant is judged necessary.

Animals↗
PubMed2003

[Protocol for adapting treatment with vitamin K antagonists before dental extraction].

BACKGROUND: The purpose of this study was to validate a protocol for dental extraction in patients taking vitamin K antagonists without changing the treatment when the INR is lower than 2.8. MATERIAL AND METHODS: One hundred four extractions (96 patients) were performed during a 9 month period in patients taking vitamin K antagonists. Extraction was performed when the international normalized ratio (INR) was less than 2.8, otherwise, the treatment was modified until the desired INR was reached. Extractions were performed under para-apical and alveolar local anesthesia and sutured with hemostatic gauze. RESULTS: Three patients developed postoperative bleeding requiring alveolar revision with local application of tranexamic acid and in one case use of a biological glue. DISCUSSION: The following protocol can be proposed: ambulatory extraction under local anesthesia with an INR the day before extraction: the extraction is performed if the INR is<=2.8 using hemostatic gauze suture and tranexamic acid in case of persistent bleeding.

Adolescent↗
PubMed2003

[Brain abscess and diffuse cervico-facial cellulitis: complication after mandibular third molar extraction].

The authors report a case of cervico-facial cellulitis with brain abscess after mandibular third molar removal. This is the observation of a 26 years old boy surgically treated for a cervico-facial cellulitis ten days after a third molar's removal. He was given anti-inflammatory drugs after removal for analgesia. After a phase of clinical improving, the patient developed pulmonary and brain abscess with neurological signs. He needed neurosurgery in emergency. After eight weeks of antibiotic treatment, the patient was cured with aftereffects (jaw constriction and sensory disorders of the right thigh). Cerebro-meningeal complications of diffuse cervico-facial cellulitis are exceptional but are responsible for heavy aftereffects. This observation confirms that using anti-inflammatory drugs for analgesia is associated with a higher rate of complications after dental removal.

Adult↗
PubMed2003

[Results of an evaluation of clinical practice in orthognathic surgery in France in 2002].

BACKGROUND: Over the years, orthognathic surgery has become a mainstay of maxillofacial surgery and is the object of many publications and oral communications. However, in spite of well-established methodology, disparities still exist in France basically concerning the way orthognathic surgery is performed. MATERIALS AND METHODS: In relation with the XXXIXth congress of Stomatology and Maxillofacial surgery, a questionnaire was mailed to 100 French maxillofacial surgeons. Questions dealing with some practical points of orthognathic surgery (condylar positioning, osteosynthesis technique, rate of condylar resorption.) were asked. RESULTS: Overall reply rate was 37%. Condylar positioning was performed empirically in 73% of the cases. Mandibular osteosynthesis was achieved by titanium miniplates alone in 70%. Post-operative condylar resorption rate was about 2%. This survey produced numerous astute comments. DISCUSSION: This survey highlighted the interest of maxillofacial surgeons for practical aspects of orthognathic surgery including the questions of condylar positioning or osteosynthesis technique. These points are instrumental in achieving high-quality surgical result.

Bone Plates↗
PubMed2002

[Cutaneous angiosarcoma of the head: three cases].

Cutaneous angiosarcoma of the head is an uncommon finding. We report three cases, two women with a scalp localization and a man with a facial (frontal) localization. Recurrence was observed in one woman after surgery; this patient was given palliative treatment due to her poor health condition. The other women experienced three recurrences. After the last surgery, latissmus dorsi free flap graft, she has been disease free. The man was treated with surgery and radiotherapy. Regional lymph node metastasis appeared 5 years after the initial treatment. He is now disease free after surgery and cervical radiotherapy. Wide surgery and careful long-term follow-up are essential. The latissimus dorsi free flap can provide successful cure.

Aged↗
PubMed2002

[The retromolar area, an alternative for the mandibular symphisis graft in implant surgery: quantitative and qualitative analysis of 52 samples].

BACKGROUND: We conducted an comparative anatomy study of two sites for harvesting bone grafts for implant surgery: the mandibular symphysis and the ramus area. MATERIAL AND METHOD: Fifty-two anatomical specimens were studied (34 from the retormolar region and 18 from the symphysis region. Measurement were: size, weight, bone volume, bone density, cortical/cancellous ratio. RESULTS: Samples from the two sites gave equivalent results. DISCUSSION: We describe the harvesting method and the difficulties encountered at each site. The retromolar site appears to be an attractive alternative to the symphysis region for bone graft harvesting.

Bone Density↗
PubMed2001

Novel microparticulate system made of poly(methylidene malonate 2.1.2).

Formulation of PMM 2.1.2 microparticles entrapping ovalbumin as a model protein was achieved by using a double emulsion solvent evaporation method. Parameters such as the nature of the solvent, polymer concentration and polymer molecular weight were investigated. Preparation process led to the formation of spherical and smooth particles with a mean diameter of 5 microm, and an encapsulation efficiency and protein loading level of up to 16 and 2.9% w/w, respectively. After an initial burst of approximately 10%, the protein was released at a rate of less than 1% per day. This slow release kinetics of encapsulated ovalbumin in phosphate buffer indicates that most of the protein was encapsulated within the polymer matrix. Degradation of PMM 2.1.2 microparticles in the presence of esterases indicated that side chain hydrolysis of the polymer was the rate-determining step in bioerosion; cleavage of the ester side chain, which was further hydrolyzed to glycolic acid and ethanol, led to an acrylic acid and subsequent solubilization of the polymer. However, slow polymer backbone solubilization after degradation was observed.

Biocompatible Materials↗
PubMed2001

In vitro and in vivo evaluation of poly(methylidene malonate 2.1.2) microparticles behavior for oral administration.

The goal of this paper was to investigate the fate of novel poly(methylidene malonate 2.1.2) microparticles with different surface properties, i.e. prepared with or without polyvinylalcohol (PVA), after oral administration, using in vitro cell culture and an in vivo mice model. Incubation of particles with Caco-2 cells induced no cytotoxicity except for the microparticles prepared without PVA at high concentrations. At subtoxic concentrations, microparticles were highly associated to cells, independently of particles concentrations, particles surface properties (with or without PVA) or incubation time. Confocal microscopy analysis revealed that adsorption was the main phenomenon leading to the association of particles to cells. However, association was greater at 37 degrees C than at 4 degrees C, suggesting that an active process, such as endocytosis, could also occur. In vivo, radiolabeled particles were mainly found in luminal content and also adsorbed onto the epithelium. After 24 hours, more than 15% of PVA-free microparticles were still present in the gastrointestinal tract, compared to 5% for particles prepared with PVA. However, histological evaluation revealed low uptake of particles by Peyer's patches. As a conclusion, this study provided a good correlation between in vitro and in vivo evaluation. These particles could be useful for oral sustained release and delivery of drugs to intestinal and colon epithelium.

Administration, Oral↗
PubMed2001

[Perioperative medical complications in orthognathic surgery].

PURPOSE: To describe per and postoperative medical complications. STUDY DESIGN: Prospective, observational study. PATIENTS: Between July and December 1999, 59 patients scheduled for programmed orthognathic surgery were included. METHODS: Anaesthetic and surgical procedures were standardised including patient information and training of surgical ward' nurses. During perioperative periods (in operative and recovery theater and in surgical ward), all the events were qualified on an anaesthetic spreadsheet for a qualitative analysis (description of events and treatment procedures). RESULTS: Two main complications were described 1) one atelectasia due to blood inhalation during the recovery period and 2) local sepsis in surgical ward. These two events were medically treated and recovered. No need of blood transfusion or stay in ICU were noted. CONCLUSION: Anaesthetic and surgical cooperation is associated with poor morbidity of this functional surgery performed in young subjects.

Adolescent↗
PubMed2001

[Lactic acid polymer implants in the repair of traumatic defects of the orbital floor].

BACKGROUND: The criteria determining the choice of the technique used to repair traumatic orbital floor defects include the quality of the expected result, morbidity, ease of use and plasticity of the method, and its cost and availability. Among the different methods proposed, lactic acid polymer implants are particularly interesting. MATERIAL AND METHODS: Eighteen patients with an isolated blow-out fracture of the orbital floor were treated with a lactic acid polymer implant between 1995 and 1996. Ten of these patients were reviewed at 24 to 43 months follow-up. RESULTS: The mean age of the patients was 35 years (20-52 years). No residual diplopia was observed. None of the patients had an anomalous orbital volume or ocular dystopia. None of the implants migrated. One patient experienced episodes of palpebral inflammation that resolved spontaneously. The ten patients reviewed were satisfied with the outcome. DISCUSSION: The properties of lactic acid polymer implants facilitate their use, avoid morbidity and provide a quality result. This is the procedure of choice for repairing tissue loss of the orbital floor. It has several advantages over alternative methods (the implants are rigid, thin, resorbable and well tolerated) without having their defects (thickness, fragility, roughness, predetermined form, rapid alteration, specific instrumentation, iatrogenic disorders). In addition, lactic acid polymer plates can be remodeled when heated, allowing a precise adaptation of the implant to the orbital structures. Finally, the cost, compared with the advantages, is not a barrier for routine use.

Absorbable Implants↗
PubMed2001

[Primary osseous leiomyosarcoma of the jaw. Apropos of a case].

Primary leiomyosarcoma of bone is a malignant smooth muscle tumour uncommonly found in the jaws. We report a case of primary leiomyosarcoma of the mandible in a 31-year-old man treated with wide resection and radiotherapy then secondary reconstruction with a fibula free flap. No recurrence or distant metastasis has developed four years after the initial surgery. We review the literature on primary leiomyosarcoma of the jaws.

Adult↗
PubMed2000

Structure elucidation of methylidene malonate 2.1.2 cyclic trimers with mass spectrometry, liquid chromatography and nuclear magnetic resonance investigations.

The anionic polymerization of methylidene malonate 2.1.2. is able to yield four different molecule types. The major product obtained at pH 5.5 corresponds to a trisubstituted cyclohexanone formed by a back-biting reaction. A mixture of four diastereoisomer couples due to the presence of three asymmetric carbon atoms was produced in the same proportion. These results were deduced from mass spectrometry (MS), liquid chromatography MS (LC-MS) and 1H nuclear magnetic resonance (NMR) investigations.

Chromatography, High Pressure Liquid↗
PubMed2000

[Treatment of low-pressure vascular malformations by injection of Ethibloc. Study of 19 cases and analysis of complications].

We retrospectively studied the cases of 19 patients suffering from low flow vascular malformations who were treated with Ethibloc sclerotherapy. Out of 10 venous angiomas, 5 entirely disappeared, 3 considerably decreased and 2 remained unaltered. Out of 7 cystic lymphangiomas, 7 were completely cured and in the 2 other cases, outcome was quite good. Post-treatment complications consisted in a local inflammatory reaction. This reaction occurred immediately and disappeared within a few days without after-effects. It materialized as an Ethibloc exteriorization among 5 patients suffering from venous angiomas and 3 patients suffering from lymphangiomas and as an inflammatory lump for 2 venous angiomas carriers and for 4 lymphangiomas carriers. This lump was located at the puncture point of the product and it was due to some Ethibloc residue. Fourteen of these local reactions spontaneously decreased; 5 of them required a surgical operation but in all cases, after-effects were minor. These satisfactory results (volume decreasing in 90% of the malformations) as well as the mildness of the side effects encourage to use Ethibloc in the treatment of low flow vascular malformations. In our experience, Ethibloc is particularly appropriate for the treatment of large lymphangiomas.

Adult↗
PubMed1999

Cross-polarization/magic-angle-spinning nuclear magnetic resonance in selectively 13C-labeled synthetic eumelanins.

We report a solid-state NMR study of synthetic eumelanins prepared by oxidation of 5,6-dihydroxyindole (DHI) selectively 13C-labeled at positions 2 or 3 of the indole ring. The 13C-1H couplings have been used to quantify the carbons by selecting the non-protonated and protonated carbon resonances. By comparing the data of non-labeled melanin to that obtained using [2-(13)C]- and [3-(13)C]-enriched DHI, it was possible to clearly demonstrate the high chemical reactivity of position 2 and, to a lesser extent, position 3 of the DHI unit. These two sites together are responsible for three-quarters of the proton loss during polymerization. The cross-polarization/magic-angle-spinning spectra likewise point to a partial oxidation of positions 2 and 3 to the carboxyl and carbonyl oxidation states during the formation of melanin. Furthermore, it is shown that 13C-13C dipolar interactions in [2-(13)C]-enriched DHI melanins can be observed using radiofrequency-driven dipolar recoupling (RFDR) 2D experiments. An upper limit of about 4 A for the distance between the C-2 carbons is deduced from the RFDR experiments. This result is in agreement with the basic arrangement of the different atoms expected in the DHI melanins.

Carbon Isotopes↗