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Biomedical subjects

Serge Mordon

Publications and source records attributed to Serge Mordon.

31 records · Page 2Linked to original sources
PubMed2004

Treatment of neck lines and forehead rhytids with a nonablative 1540-nm Er:glass laser: a controlled clinical study combined with the measurement of the thickness and the mechanical properties of the skin.

BACKGROUND: Nonablative remodeling has been recently proposed as a new, no-down-time, anti-aging treatment. Objective. The objective was to evaluate the efficacy and safety of nonablative skin remodeling with a 1540-nm Er:Glass laser on neck lines and forehead rhytids. METHODS: Twenty female patients (mean age 45 years) were enrolled. Skin thickness and mechanical properties were measured before the first treatment, 1 month after the third treatment, 1 month after the fifth treatment, and 3 months after the fifth treatment. RESULTS: All patients reported an improvement in both skin tone and texture. Using ultrasound imaging, dermal thickness of neck and forehead increased, respectively, by 70+/-13 microm (p<0.001) and 110+/-19 microm (p<0.003). A dramatic increase of initial stress of the forehead skin (firmness) was obtained, from 7.62+/-3.68 before treatment to 16.68+/-7.44 3 months after the fifth treatment (p<0.0002). No immediate or late adverse effects were noted throughout the treatment regimen. CONCLUSION: This study demonstrates that irradiation with a 1540-nm Er:Glass laser emitting in a pulsed mode and coupled with an efficient contact cooling system increases dermal thickness and firmness, leading to a clinical improvement of neck lines and forehead rhydits.

Adult↗
PubMed2004

In vivo imaging of bioluminescent Escherichia coli in a cutaneous wound infection model for evaluation of an antibiotic therapy.

A rapid, continuous method for noninvasively monitoring the effectiveness of several antibacterial agents in real time by using a model of wound infection was developed. This study was divided into three steps: (i) construction of a plasmid to transform Escherichia coli into a bioluminescent variant, (ii) study of the bioluminescent E. coli in vitro as a function of temperature and pH, and (iii) determination of the MIC and the minimal bactericidal concentration of sulfamethoxazole-trimethoprim (SMX-TMP). Finally, the efficacy of SMX-TMP was monitored in vivo in a cutaneous wound model (hairless rat) infected with this bioluminescent bacterium by using a bioluminescence imaging system. E. coli was transformed by electroporation with a shuttle vector (pRB474) containing the firefly (Photinus pyralis) luciferase gene, resulting in a bioluminescent phenotype. It was found that pH 5.0 was optimal for incorporation of the susbstrate D-luciferin for the luciferase reaction. In vitro, when the agar dilution method, standard turbidity assays, and the bioluminescence imaging system were used, E. coli(pRB474) proved to be susceptible to SMX-TMP. In vivo, at 4 h, SMX-TMP treatment was already efficient compared to no treatment (P = 0.034). At 48 h, no bioluminescence was detected in the wound, demonstrating the susceptibility of E. coli to SMX-TMP. In conclusion, this study points out the advantage of using bioluminescence imaging to evaluate the effects of antibiotics for the treatment of acute infections in vivo in a nondestructive and noninvasive manner.

Animals↗
PubMed2003

Using a "non uniform pulse sequence" can improve selective coagulation with a Nd:YAG laser (1.06 microm) thanks to Met-hemoglobin absorption: a clinical study on blue leg veins.

BACKGROUND AND OBJECTIVES: Evaluation of the efficacy, on 1-2 mm blue leg telangiectasia, of a 1,064 nm Nd:YAG laser emitting in a non uniform pulse sequence calculated to consider Met-Hb formation during laser irradiation of a blood vessel. MATERIALS AND METHODS: A 1,064 nm Nd:YAG laser (Quantel Medical, Athos, France) was used in a non uniform pulse sequence mode, fluences: 300-360 J/cm(2) spot: 2 mm, + 5 degrees C contact cooling. The clinical evaluation was performed on 11 female patients, average age: 43 (25-57) years, phototype I-VI. All subjects were previously examined with Doppler ultrasound. A treatment site (6 x 4 cm) was selected on each patient. The topography of the vessels network was reported on a tracing plastic frame before each session and 6 weeks after the last one. These frames were digitized and the number of vessels was determined using the Digitized Tracing Frames Technique. Side effects were noted before and after every treatment, and 6 weeks after the last one. This study lasted for 10 months. RESULTS AND DISCUSSIONS: Patients tolerated the procedure without anesthesia. Moderate pain, transient erythema and edema, one hyperpigmentation and one matting were noted. There was no hypopigmentation. 55% (P < 0.002) vessels clearance after one session, 86% after two sessions (P < 0.001), and 98% (P < 0.001) after three sessions were obtained. On two patients, the treatment was completed after two sessions with a full clearance. Data reported in this study were obtained thanks to a computerized calculation of vessels clearance. They are similar or superior to those reported in the literature about 1,064 nm Nd:YAG lasers and leg telangiectasia. CONCLUSIONS: Since, it was developed to consider the modification of blood absorption and the methemoglobin formation which leads to an increase of the 1.06 microm wavelength absorption, the non uniform pulse mode emphasizes the efficacy of this 1,064 nm Nd:YAG laser concerning the treatment of blue leg veins telangiectasia between 1 and 2 mm. This mode gives the possibility to deliver high energy while preserving the surrounding tissue and leads to a rapid vessel clearance with reduced pain and few side effects when compared to previously published clinical studies using a 1.06 microm laser.

Adult↗
PubMed2003

Transpupillary thermotherapy (TTT) with short duration laser exposures induce heat shock protein (HSP) hyperexpression on choroidoretinal layers.

BACKGROUND AND OBJECTIVES: To assess a choroidal heat shock protein hyperexpression after transpupillary thermotherapy (TTT) performed with exposures shorter than 60 seconds. STUDY DESIGN/MATERIALS AND METHODS: Nine male pigmented rabbits were anesthetized and TTT was performed on their right eye with a 810 nm diode laser (Iridis, Quantel-Medical (France)) (spot size: 1.3 mm). Three exposure durations (60, 30, or 15 seconds) were used with three ranges of power for each duration ("high," "mild," or "low"). A series of laser impacts was delivered to the posterior pole of the retina. Left eyes were used as controls. Twenty-four hours after laser irradiation, the animals were killed and histological study was performed on chorioretinal layers. Tissue samples were fixed in formalin and embedded in paraffin. A monoclonal antibody was used to detect Hsp70 immunoreactivity (mouse IgGl, SPA-810, Stress Gen, Victoria, BC, Canada), followed by a biotinylated goat anti-mouse antibody (Dako, Glostrup, Denmark), revealed by the avidin-biotin complex (Vectastain kit, Vector Laboratries, Burlingame, CA, USA) and the AEC chromogen. Retinal structures were further identified by HES coloration. RESULTS: During the experiments, the laser spots were not visible except for the strongest "high" powers for each exposure duration, where a whitening was discernable at the end of the laser exposures. A strong HSP70 immunoreactivity was detected in choroidal, non-pigmented cells for laser exposures lasting 60, 30, or 15 seconds with "mild" laser powers. On the contrary, rare HSP hyperexpression was detected with "high" or "low" laser powers lasting 60, 30, or 15 seconds. No HSP-70 immunoreactivity was detected on control eyes nor outside of the irradiated zones of treated eyes. CONCLUSIONS: Transpupillary laser irradiation lasting 15, 30, or 60 seconds induces an hyperexpression of HSP on choroidal layers. This could be a basis for the use of TTT with "short" laser exposures.

Animals↗
PubMed2003

Site-specific methylene blue delivery to pilosebaceous structures using highly porous nylon microspheres: an experimental evaluation.

PURPOSE: This study aimed to evaluate the penetration of methylene blue (MB)-loaded microspheres into pilosebaceous structures of rats. MATERIALS AND METHODS: MB was incorporated into 5 microm highly porous nylon microspheres. The microspheres were dispersed into fluid silicone. Male hairless rats were used to evaluate the penetration of MB into hair follicles. After formulation application, MB diffusion was induced and skin biopsies were realized immediately, 2 and 26 hours after MB loaded microspheres application. MB fluorescence was observed with a microscope expanded for fluorescence microscopy. RESULTS: Position of microspheres and MB diffusion was dependent on delay between microspheres application and harvest. Inside the skin, MB was seen exclusively in the hair follicle and the sebaceous glands. MB diffusion varied from 160+/-50 microm (2 hours after application) to 410+/-70 microm (26 hours after application). MB was also found in the sebaceous glands. DISCUSSION: This study confirms that 5 micro m microspheres are optimally deposited deep within the pilosebaceous structure. In agreement with the literature, when microspheres are topically applied on the skin, they penetrate via a "lipid-rich channel" coating the hair follicles. MB is exclusively distributed in the hair follicles and their accessories. CONCLUSION: This report presents evidence of MB pilosebaceous delivery through the use of microsphere formulation. This is obtained thanks to topical enhancement via the follicular route. This drug delivery system aims to transport MB into the pilosebaceous unit specifically and deeply. Various other applications could derive from this work. For example, such a method might be used to increase the therapeutic index of drugs directed at hair sebaceous gland disorders. Laser treatment of acne or laser hair removal could also benefit of this technique.

Animals↗
PubMed2003

Can thermal lasers promote skin wound healing?

Lasers are now widely used for treating numerous cutaneous lesions, for scar revision (hypertrophic and keloid scars), for tissue welding, and for skin resurfacing and remodeling (wrinkle removal). In these procedures lasers are used to generate heat. The modulation of the effect (volatilization, coagulation, hyperthermia) of the laser is obtained by using different wavelengths and laser parameters. The heat source obtained by conversion of light into heat can be very superficial, yet intense, if the laser light is well absorbed (far-infrared:CO(2) or Erbium:Yttrium Aluminum Garnet [Er:YAG] lasers), or it can be much deeper and less intense if the laser light is less absorbed by the skin (visible or near-infrared). Lasers transfer energy, in the form of heat, to surrounding tissues and, regardless of the laser used, a 45-50 degrees C temperature gradient will be obtained in the surrounding skin. If a wound healing process exists, it is a result of live cells reacting to this low temperature increase. The generated supraphysiologic level of heat is able to induce a heat shock response (HSR), which can be defined as the temporary changes in cellular metabolism. These changes are rapid and transient, and are characterized by the production of a small family of proteins termed the heat shock proteins (HSP). Recent experimental studies have clearly demonstrated that HSP 70, which is over-expressed following laser irradiation, could play a role with a coordinated expression of other growth factors such as transforming growth factor (TGF)-beta. TGF-beta is known to be a key element in the inflammatory response and the fibrogenic process. In this process, the fibroblasts are the key cells since they produce collagen and extracellular matrix. In conclusion, the analysis of the literature, and the fundamental considerations concerning the healing process when using thermal lasers, are in favor of a modification of the growth factors synthesis after laser irradiation, induced by an HSR. An extensive review of the different techniques and several clinical studies confirm that thermal lasers could effectively promote skin wound healing, if they are used in a controlled manner.

Cicatrix↗
PubMed2002

Study of platelet behavior in vivo after endothelial stimulation with laser irradiation using fluorescence intravital videomicroscopy and PEGylated liposome staining.

Platelets contain an array of potent proinflammatory mediators, and therefore they are regarded as mediator and effector cells in inflammation. Knowing the role of platelets during these processes is crucial and the analysis of their behavior in situ and the associated mechanisms is consequently particularly important. However, conventional in vitro staining techniques induce modification of the characteristics of platelets. This study aimed to evaluate platelet behavior in vivo after endothelial stimulation (without endothelial denudation or exposure of basal lamina and/or collagen) with an argon laser, using video intravital microscopy in combination with a new an innovative platelet staining technique based on polyethyleneglycol (PEG) liposomes. The study was performed on skin by using a dorsal skin-fold chamber implanted in golden hamsters. Platelets were stained by 5,6-CF-encapsulated PEGylated liposomes injected intravenously. The skin microcirculation was observed with an intravital microscope (using x25, x40, and x80 magnifications) fitted with a xenon light source, an epifluorescence assembly, and an ultra-high sensitivity video camera for fluorescence imaging. Platelet activation without endothelial denudation or exposure of basal lamina and/or collagen was obtained with an argon laser emitting at 514.5 nm with the following parameters: 20 mW, 300 ms, 120 J/cm(2). The 80-microm laser beam was focused on a vessel and its position was controlled with the microscope. Thanks to the spatial resolution of the intravital microscopic imaging system, the platelets were seen rolling individually on the endothelium. After laser stimulation, platelets were activated and three phases were observed: recruitment, adhesion and detachment. The observation of these three phases was time dependent and the kinetics of the process were quantified. The recruitment reached a maximum after 90 +/- 20 s. The adhesion phase lasted for 110 +/- 25 s. At last, detachment of all platelets was observed. This detachment started 200 +/- 20 s after irradiation and was completed in less than 2 min. This study confirms that laser irradiation used with optimal parameters can induce platelet activation without thrombus formation. Platelets can adhere only transiently on stimulated endothelium. This phenomenon may therefore represent a defense mechanism, by which platelets would accumulate in the vicinity of an injury, making them available for immediate response. At last, this study has clearly demonstrated the advantages of our new and innovative platelet staining method using PEGylated liposomes, which are (i) in situ labeling, (ii) use of a hydrophilic marker located in an aqueous compartment within the platelet, and (iii) labeling of platelets allowing observation during the whole experiment.

Animals↗
PubMed2002

Determination of optimal parameters for laser for nonablative remodeling with a 1.54 microm Er:glass laser: a dose-response study.

BACKGROUND: Nonablative subsurface heating is a challenge for medical laser companies. Among the different lasers proposed today, the erbium-glass (Er:glass) laser combined with contact cooling could be an alternative for nonablative remodeling. OBJECTIVE: To investigate the risk of side effects according to the quality of cooling and number of pulses. METHODS: A clinical evaluation was performed on 10 patients using an Er:glass laser (1.54 microm) with contact sapphire cooling handpiece (+5 degrees C). Periorbital and perioral areas were treated with a number of pulses increasing gradually from three to eight for a total energy of 24-64 J/cm2. The presence or absence of swelling, crust, blister, and erythema were graded at 7 days. At 3 months postoperatively, hypopigmentation, hyperpigmentation, textural changes, and scars were evaluated clinically. RESULTS: Periorbital and perioral areas respond differently to the number of pulses defining a "safe" clinical threshold. The periorbital site is very sensitive to dermal heating and efficacy of contact cooling; the anatomic features of this body location may explain these differences. CONCLUSION: Selective dermal heating can be achieved with an Er:glass laser coupled with a contact cooling handpiece. The quality of the contact cooling and the number of pulses appear to be important parameters for safety and reproducible clinical results.

Adult↗
PubMed2002

Nonablative remodeling: a 14-month clinical ultrasound imaging and profilometric evaluation of a 1540 nm Er:Glass laser.

BACKGROUND: Nonablative remodeling has been recently proposed as a new antiaging treatment with no downtime. OBJECTIVE: To evaluate the efficacy and safety of nonablative skin remodeling with a 1540 nm Er:glass laser and contact cooling on perioral and periorbital rhytides at 14 months follow-up. METHODS: Forty-two female patients (mean age 47 years), Fitzpatrick skin types I-IV were treated five times at 6-week intervals and checked 6 months after the last treatment. Patients were evaluated using clinical data, patient satisfaction (scale 1-4), digital pictures, ultrasound imaging, and profilometry data from silicone imprints in order to quantify the degree of improvement. RESULTS: All subjects reported an improvement in the quality and visual aspect of their skin at 6 months (mean patient satisfaction 3.06/4) and at 14 months after enrollment (mean patient satisfaction 2.90/4). This was confirmed by a 43.41% reduction of anisotropy (P < 0.001) 6 weeks after the fourth treatment, reaching 44.85% reduction 6 months after the fifth treatment (P <.001). Ultrasound imaging demonstrated a 17% increase in dermal thickness (P <.001) at 6 months and 11% 6 months after the last treatment (P <.05). A lack of immediate or late adverse effects was noted at all stages of the procedure. CONCLUSION: This study demonstrated that irradiation with a 1540 nm Er:glass laser emitting in a pulsed mode and coupled with an efficient cooling system increased dermal thickness, reduced the anisotropy of the skin, and improved clinical aspects. The lack of adverse effects within the 14 months confirmed that this procedure was safe. Overall the stability of the results many months after the treatment was remarkable.

Adult↗
PubMed2002

Noninvasive fluorescent study in situ and in real time of glucose effects on the pharmacokinetic of calcein.

This study was undertaken to compare the effect of glucose injection on the pharmacokinetic behavior of a soluble dye in normal and tumoral tissues. The measurements were done using a noninvasive fluorescent spectroscopy in situ and in real time. The experiments were performed on three groups of animals with calcein as a soluble pH-insensitive fluorescent dye combined or not with glucose. Glucose solution was injected 5 or 30 min before calcein. Fluorescence emission intensity was recorded on normal and tumor tissues with an optical multichannel analyzer. Calcein concentration was also measured in blood using repetitive blood sampling. In the control group (without glucose injection), calcein is rapidly cleared from the blood, with a slow tissue clearance. Fluorescence of normal tissue was higher than fluorescence measured in tumor tissue. When glucose is injected 5 min before calcein, there was a rapid increase of tissue fluorescence followed by a plateau remaining during the whole experiment. No difference between tumor and normal tissue fluorescence intensity was observed. When glucose was injected 30 min before calcein, the plateau phase was reduced to 50 min in normal tissue. Tumor tissue fluorescence displays no distinct plateau phase. These results clearly showed the effect of glucose injection in situ and in real time, by a noninvasive method, on the pharmacokinetic of a soluble dye in a tumor tissue compared to a normal tissue. Differences between blood compartment and tissues kinetic profiles were also clearly demonstrated.

Animals↗
PubMedDate not supplied

Raman microspectrometry of laser-reshaped rabbit auricular cartilage: preliminary study on laser-induced cartilage mineralization.

Laser-assisted cartilage reshaping (LACR) is a relatively novel technique designed to noninvasively and permanently restructure cartilaginous tissue. It is believed that heat-induced stress relaxation, in which a temperature-mediated disruption of H2O binding is associated with conformational alterations in the proteoglycan and collagen-rich matrix, constitutes the underlying mechanism of LACR. Several reports have suggested that laser-mediated cartilage mineralization may contribute to the permanent shape change of laser-reshaped cartilage. In an effort to validate these results in the context of Er:glass LACR, we performed a preliminary Raman microspectrometric study to characterize the crystal deposits in laser-irradiated chondrocytes and extracellular matrix. For the first time, we identified intracellular calcium sulfate deposits and extracellular calcium phosphate (apatite) crystals in laser-reshaped rabbit auricular cartilage. Calcium carbonate deposits are localized in both irradiated and nonirradiated samples, suggesting that this mineral plays no role in conformational retention. In our discussion, we elaborate on the possible molecular and cellular mechanisms responsible for intra- and extracellular crystallization, and propose a novel hypothesis on the formation of apatite, inasmuch as the biological function of this mineral (providing structure and rigidity in bones and dental enamel) may be extrapolated to the permanent shape change of laser-irradiated cartilage.

Animals↗
PubMedDate not supplied

Laparoscopic photodynamic diagnosis of ovarian cancer peritoneal micro metastasis: an experimental study.

The goal of this study was to assess the interest of photodynamic diagnosis (PDD) for laparoscopic detection of peritoneal micro metastasis in ovarian carcinoma. Using an experimental animal model, intraperitoneal injection of aminolevulinic acid (ALA) and hexylester of aminolevulinic acid (He-ALA) were compared in order to improve laparoscopic detection of ovarian peritoneal carcinomatosis. Twenty-one 344 Fischer female rats received an intra peritoneal injection of 106 NuTu-19 cells. At day 22, carcinomatosis with micro peritoneal metastasis was obtained. Rats were randomized in three groups concerning intra peritoneal injection before laparoscopic staging: 5-ALA hydrochloride, HE-ALA and sterile water. Using D Light system, laparoscopic peritoneal exploration was performed with white light (WL) first and then with blue light (BL). The main objective was to assess feasibility and sensibility of laparoscopic PDD for nonvisible peritoneal micro metastasis of ovarian cancer. The main parameter was the confirmation of neoplasic status of fluorescent foci by histology. Concerning PDD after intraperitoneal injection of 5-ALA, mean values of lesions seen is higher than without fluorescence (32 vs 20.7; P = 0.01). Using He-ALA, mean values of detected lesions is higher than without fluorescence (42.9 vs 33.6; P < 0.001). Neoplasic status of fluorescent foci was confirmed in 92.8% of cases (39/42). Using 5-ALA, fluorescence of cancerous tissue is significantly higher than that of normal tissue in all the rats (ratio 1.17) (P = 0.01). With He-ALA, intensity of fluorescence is significantly higher in cancerous tissue compared to normal tissue, irrespective of the rat studied (ratio 1.22; P < 0.001).

Aminolevulinic Acid↗