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Biomedical subjects

L Michel

Publications and source records attributed to L Michel.

At least 19 recordsLinked to original sources
PubMed2006

Chemical composition and in vitro antifungal and antioxidant activity of the essential oil and methanolic extract of Teucrium sauvagei Le Houerou.

The chemical composition and the in vitro antifungal and antioxidant activity of the essential oil and the methanolic leaf extracts of Teucrium sauvagei Le Houerou, an endemic medicinal plant growing in Tunisia, have been studied. More than 35 constituents having an abundance >or=0.2% were identified in the oil. beta-Eudesmol, T-cadinol, alpha-thujene, gamma-cadinene, and sabinene were the prevalent constituents. Results of the antifungal activity tests indicated that the methanolic extract inhibited the in vitro growth of seven dermatophytes, whereas the essential oil showed average inhibition against only three dermatophytes. In vitro antioxidant properties of the essential oil and the methanolic extract were determined by DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2'-azinobis(3-ethylbenzothiazoline-6-sulphonic acid)) assays and compared to those of the synthetic antioxidant Trolox. Due to their antifungal and antioxidant properties, the essential oil and the methanolic extract of T. sauvagei may be of use as natural preservative ingredients in food and/or pharmaceutical industries.

Antifungal Agents↗
PubMed2004

Expression of endothelin-1 by adrenocortical carcinoma: a new target for anti-cancer therapy?

Adrenocortical carcinoma is a rare neoplasm with poor prognosis. Endothelin-1 (ET-1) has been implicated in carcinogenesis, but has never been studied in this neoplasm. A 76-year-old woman with Cushing's syndrome due adrenocortical carcinoma was operated on and the tumour removed was studied by immunohistochemistry for ET-1. Patient history illustrates the poor prognosis of this cancer that became metastatic after one year. Immunohistochemical studies disclosed a strong expression of ET-1 by adrenocortical carcinoma cells. As shown in other cancers, ET-1 expression by adrenocortical carcinoma may suggest a pathogenic role of ET-1 in tumorigenesis that possibly could be countered by ET-1 receptor antagonists. These agents could open new therapeutic perspectives to treat a carcinoma known to have a poor prognosis.

Adrenal Cortex Neoplasms↗
PubMed2004

[Vocal rehabilitation with tracheoesophageal prosthesis. Study of peri-prosthetic leakages].

OBJECTIVES: Peri-prosthetic leakages are a frequent complication of tracheoesophageal prosthesis used in the vocal rehabilitation of laryngectomized patients. The authors examine the effect of pre or post operative radiotherapy upon the incidence of this complication. MATERIALS AND METHOD: In a retrospective study of 67 patients rehabilited with a phonatory prosthesis between 1993 and 2002, pre or post-operative radiotherapy was carried out in 61 patients. RESULTS: A peri-prosthetic leakage occured in 38.8% of the cases. The pre or post-operative radiotherapy was not a statistically significant cause of leakage, as the age of the patient and the surgical procedure. CONCLUSION: Although not supported by the statistical study because of a lack of cases, the radiotherapy remains for the authors a factor determining in the mechanism of the peri-prosthetic leakages and bad forecast for their treatment. Realized before the surgery, it contra-indicates the phonatory prosthesis at the time of the tumor resection. In case of post-operative radiotherapy, the risks must be clearly explained to the patient.

Female↗
PubMed2004

[The verrucous laryngeal carcinoma. A rare tumor with a difficult diagnosis].

OBJECTIVES: The authors report a single case of laryngeal verrucous carcinoma and review the literature. MATERIALS AND METHOD: The delay of the diagnosis, the difficulties in its establishment and the therapeutic methods are discussed in a review of the literature. RESULTS: Histopathological diagnosis remains difficult. This may explain a great number of mistakes and the subsequent delay of in treatment. The role of radiotherapy is discussed. CONCLUSION: The diagnosis and management of the laryngeal verrucous carcinoma is difficult.

Carcinoma, Verrucous↗
PubMed2003

Size and geometry of hepatic radiofrequency lesions.

AIM: To report and compare the size and geometry of hepatic radiofrequency (RF) lesions using the currently available commercial devices. METHODS: A literature search was carried out for the period from January 1st 1990 to June 15th 2003. The commercial suppliers were asked to provide all available data. For each electrode and protocol, size and geometry of single-cycle thermal lesions were registered. RESULTS: No information at all on size and geometry of the inducible lesions was available for 17 of the 28 current commercial electrodes. Many descriptions of RF lesions are limited to the mean transverse diameter. With normal blood flow, diameter of lesions is often smaller than suggested by the length of the electrode tip or the diameter of the deployed prongs. Lesions are rarely perfect spheres but either ellipses or flattened spheres. Distortion of the RF lesion by nearby blood vessels is very common. Fusion of thermal zones between prongs of expandable electrodes can be incomplete. Blood flow interruption using a Pringle maneuver yields larger lesions that are less distorted and more complete. CONCLUSIONS: There is insufficient experimental data for many electrodes that are currently used in patients. RF companies should provide these data before releasing electrodes for use. For those electrodes for which data exist, coagulation lesions are often smaller, less spherical, less complete and less regular than generally presumed. Accurate knowledge of size and geometry of RF lesions is crucial to prevent local recurrence.

Animals↗
PubMed2003

Immediate effects of UV radiation on the skin: modification by an antioxidant complex containing carotenoids.

BACKGROUND/AIMS: The ultraviolet (UV) portion of sunlight is involved in the induction and development of skin cancers against which a limited photoprotection may be provided by reduced time of exposure, clothing, and sunscreen applications. The concept of an effective, safe, systemic photoprotection will circumvent many of the shortcomings. The UV-induced oxidative stress is a cause of DNA damage and a few publications have shown, in humans, minimal benefits, if any, of the oral intake of antioxidant complex, contrasting with the large literature showing beneficial effects in vitro or in animal models. METHODS: We investigated, in 25 healthy individuals, the capacity of an antioxidant complex (AOC) - vitamins (lycopene, beta-carotene, alpha-tocopherol), selenium - to reduce UV-induced damages. The AOC was administered orally, daily during 7 weeks. Before and after irradiations, before and after the intake of the product, six parameters were studied: skin color by chromametry, minimal erythemal dose and, on skin biopsies, sunburn cells (SBCs), p53 detected by immunohistochemistry, pigmentation index, and levels of lipoperoxides (thiobarbituric acid reaction). RESULTS: After the oral intake of AOC, we observed an elevation of the actinic erythema threshold (+20%, P=0.01) and a general reduction of the UV-induced erythemas, a reduction of the UV-induced p53 expression (P<0.05) and of SBCs (P<0.01), and a parallel reduction of the lipoperoxide levels (P<0.01). The pigmentation was increased (P<0.01). CONCLUSION: After the oral intake of an antioxidant complex, many parameters of the epidermal defense against UV-induced damages are significantly improved. The oral intake of AOC could provide a safe, daylong and efficient complement to photo-protective measures provided by topical and physical agents and may contribute to reduce the DNA damages leading to skin aging and skin cancers.

Administration, Oral↗
PubMed2003

[Combined transfacial and neurosurgical approach for the treatment of ethmoid cancers].

OBJECTIVES: The purpose of this work was to examine the indications for the combined transfacial and neurosurgical approach to ethmoid cancers. PATIENTS AND METHODS: Fifteen patients with ethmoid cancers underwent surgery via the combined approach between 1990 and 2000 at the Amiens University Hospital. The transfacial approach alone was reserved for elderly patients. RESULTS: The histological diagnosis was adenocarcinoma in 10 patients. There was one postoperative death. Mean follow-up was 45 months (range 3 - 129). Six patients died from local or metastatic recurrence. At last follow-up eight patients were disease free, two had local or metastatic recurrence. CONCLUSION: We compared systematic use of the combined approach for curative surgery with surgical strategies adopted by other teams. The combined approach is indicated for T3 or T4 tumors and for all other tumors with a posterior or superior extension. Anterior and unilateral tumors may be treated with the transfacial access alone. Limited tumors without extension to the orbit or cribiform plate may be managed endoscopically. The role of histological diagnosis and the choice of the surgical approach remain to be evaluated.

Adenocarcinoma↗
PubMed2002

Complications of radiofrequency coagulation of liver tumours.

BACKGROUND: Radiofrequency coagulation (RFC) is being promoted as a novel technique with a low morbidity rate in the treatment of liver tumours. The purpose of this study was to assess critically the complication rates of RFC in centres with both large and limited initial experience, and to establish causes and possible means of prevention and treatment. METHODS: This is an exhaustive review of the world literature (articles and abstracts) up to 31 December 2001; 82 independent reports of RFC of liver tumours were analysed. RESULTS: In total, 3670 patients were treated with percutaneous, laparoscopic or open RFC. The mortality rate was 0.5 per cent. Complications occurred in 8.9 per cent: abdominal bleeding in 1.6 per cent, abdominal infection in 1.1 per cent, biliary tract damage in 1.0 per cent, liver failure in 0.8 per cent, pulmonary complications in 0.8 per cent, dispersive pad skin burn in 0.6 per cent, hepatic vascular damage in 0.6 per cent, visceral damage in 0.5 per cent, cardiac complications in 0.4 per cent, myoglobinaemia or myoglobinuria in 0.2 per cent, renal failure in 0.1 per cent, tumour seeding in 0.2 per cent, coagulopathy in 0.2 per cent, and hormonal complications in 0.1 per cent. The complication rate was 7.2, 9.5, 9.9 and 31.8 per cent after a percutaneous, laparoscopic, simple open and combined open approach respectively. The mortality rate was 0.5, 0, 0 and 4.5 per cent respectively. CONCLUSION: The morbidity and mortality of RFC, while low, is higher than previously assumed. With adequate knowledge, many complications are preventable.

Carcinoma, Hepatocellular↗
PubMed2001

Comparison of two hard keratinous substrates submitted to the action of a keratinase using an experimental design.

The influence of temperature, pH, keratinase concentration, substrate concentration and incubation time on the soluble proteins released by a new keratinase from Doratomyces microsporus was studied with a second-order experimental design. Only 15 or 18 spectrophotometric analyses were required to determine the optimal experimental conditions for this keratinase on nail and hoof. This study was carried out by measuring, according to Smith's method, the concentration of soluble proteins released by the enzyme on two substrates: nails and sheep hooves. Results give optimum conditions for the keratinase to release the soluble proteins: pH 8.2, keratinase concentration 0.14% (weight of keratinase lyophilisate/final volume) and substrate concentration 5% (weight of nail powder/final volume) for nails; temperature 38.8 degrees C, pH 9, substrate concentration 5% (weight of hoof powder/final volume) and a 5 h 55 min incubation time for hooves.

Animals↗