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Biomedical subjects

I Bonnet

Publications and source records attributed to I Bonnet.

13 recordsLinked to original sources
PubMed2004

Synthesis and characterization of polyurethane and poly(ether urethane) nanocapsules using a new technique of interfacial polycondensation combined to spontaneous emulsification.

Polyurethane polymers and poly(ether urethane) copolymers were chosen as drug carriers for alpha-tocopherol. This active ingredient is widely used as a strong antioxidant in many medical and cosmetic applications, but is rapidly degraded, because of its light, heat and oxygen sensitivity. Polyurethane and poly(ether urethane)-based nanocapsules were synthesized by interfacial reaction between two monomers. Interfacial polycondensation combined with spontaneous emulsification is a new technique for nanoparticles formation. Nanocapsules were characterized by studying particle size (150-500 nm), pH, yield of encapsulation and morphologies. Polyurethanes (PUR) were obtained from the condensation of diisocyanate (isophorone diisocyanate: IPDI) and polyol: 1,2-ethanediol (EG), 1,4-butanediol (BD), 1,6-hexanediol (HD). Poly(ether urethane) copolymers were obtained by replacing diols by polyethylene glycol oligomers (PEG) M(w) 200, 300, 400 and 600. Molecular weights of di- and polyols have a considerable influence on nanocapsules characteristics cited above. The increase of molecular weight of polyols tends to increase the mean size of nanocapsules from (232+/-3)nm using EG to (615+/-39)nm using PEG 600, and led to the apparition of a population of agglomerate particles. We also noted that the yield of encapsulation increases with the increase of polyol length (from 85.6 to 92.2% w/w). Microscopic observations confirmed particle size analysis, but cannot predict the membrane structure owing the small size of the particles.

Administration, Topical↗
PubMed1996

Acquired immunity to TNF: effects on intestinal wound healing.

Increased concentrations of tumor necrosis factor (TNF) damage normal tissue and produce a shock-like syndrome--changes that can be prevented with anti-body-specific antisera. These findings suggest that TNF-stimulated immunity should protect normal tissue and promote wound healing. To test this hypothesis, 30 Fischer 344 rats (150-200 g) were serially immunized against TNF (20 micrograms/kg). Convalescent sera assayed (micro-ELISA) for circulating antibodies revealed titers (2.54 +/- 0.08 au) significantly higher (P < 0.00001) in immunized animals than in nonimmunized controls (0.11 +/- 0.06 au). Following this, 10 immunized (Group I), 10 nonimmunized (Group II), and 10 control rats underwent partial cecectomy with primary anastomosis. Animals from Groups I and II received TNF (25 micrograms/kg) while controls received saline intravenously on Postoperative Days 1, 3, and 5. Animals were then sacrificed to determine: (1) hydroxyproline content of the anastomosis, (2) mitochondrial respiratory control ratio, and (3) pyruvate dehydrogenase activity of the muscle. We found that (1) exposure to increased concentrations of TNF (Group II) depresses (P < 0.01) biologic markers of wound healing and (2) acquired immunity to TNF (Group I) eliminates this response. In conclusion, acquired immunity to TNF protects the healing intestinal anastomosis from the effects of exposure to increased levels of TNF.

Animals↗
PubMed1995

Contaminated wounds: the effect of initial management on outcome.

Delayed primary closure has been advocated as the optimal method of management in the presence of wound contamination. The present study was performed to determine whether surgeons have accepted this standard. A total of 918 surgical wounds were evaluated and classified according to the level of contamination and type of wound management used. We found that 150 patients had a Class III or Class IV contaminated wound; however, only 21 per cent were treated with delayed primary closure. The 118 patients treated with primary closure and antibiotics had an aggregate wound infection rate of 27 per cent (Class III-29%; Class IV-24%). Only one (3%) of the wounds managed by delayed primary closure developed an infection. If infection did not occur, there was no difference in the length of stay between patients managed with primary closure and delayed primary closure. However, there was a significantly longer length of stay in the primary closure group if infection occurred. Benefit risk analysis of the patients with contaminated wounds confirmed that in this clinical setting, delayed primary closure remains the optimal method of management for the wound.

Anti-Bacterial Agents↗
PubMed1993

[Intramuscular hematoma simulating a pseudomalignant tumor].

One case of a large post-traumatic cystic haematoma of the thigh presenting with a pseudotumoral aspect, and resulting in a femoral filling defect and a spontaneous fracture 7 years later, is reported by the authors. Relationships between its pathophysiology and its consequences on bone are stressed.

Adult↗
PubMed1991

[Surgery of the lower limbs in Duchenne's muscular dystrophy].

Seventy-one children had surgical procedures on hips and/or knees and/or feet contractures before or after the age of loosing gait. Gait has been continued on 1 year and 7 months to 3 years and 8 months according to the evolving type of Duchenne Muscular Dystrophy (DMD). After analysis of results of the surgery upon contractures, surgical procedures have been determined for each joint. Before loosing gait, but when contractures were all present, surgery prolonged on gait without orthosis and relieved of physiotherapy. During the 6 months after loosing gait, surgery allowed to recover same walking ability more often with orthesis. After loosing gait, surgery gave a better comfort of life to the child and his family.

Child↗
PubMedDate not supplied

[Dementia and extrapyramidal problems caused by long-term valproic acid].

Among the side-effects attributed to valproic acid (VPA), the occurrence of Parkinsonian syndromes and cognitive impairment is very uncommonly reported. We describe five cases of reversible associated Parkinsonism. These cases were observed in epileptic patients, 57 to 74 years old, two women and three men. Extrapyramidal disorders appeared after various durations of treatment (from 6 months to 10 years). Dementia characterized by an insidious onset was associated in three cases and bradypsychia in one case. Brain pseudoatrophy was present in three patients. In all cases the signs and symptoms improved some weeks or months after discontinuation of VPA. In the literature some cases, usually in young adults or children, have been reported. In a prospective study, Armon et al. found various abnormal symptoms and signs related to motor and cognitive function impairment in patients with long-term VPA therapy. These side-effects may be related to a disturbance in the gabaergic pathways in the basal ganglia system. It is of interest to consider that delta 2-valproic acid, a metabolite of VPA, is especially accumulated in selected areas of the brain: the substantia nigra, superior and inferior colliculus, hippocampus and medulla.

Aged↗