Effects of cigarette smoking on the skin of women.
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Adult↗
Biomedical subjects
Patrice Muret
Publications and source records attributed to Patrice Muret.
Evaluation of a sunscreen photoprotective effect by ascorbic acid assessment in human dermis using microdialysis and gas chromatography mass spectrometry.
Ultraviolet irradiation causes adverse effects like sunburn, photosensitivity reactions or immunologic suppression. The aim of this study was to evaluate the photo-protective outcome of a sunscreen cream (SPF8) by the determination of erythema indexes and the assessment of ascorbic acid and its metabolites in human dermis. These substances were used as markers of oxidative effect. Eight healthy female subjects were enrolled in this study. Two abdominal areas were exposed to solar simulated irradiation with three minimal erythema dose, one with SPF8 application and the other site without SPF8 application. Two other areas were used as control, one without SPF8 application and the other site after SPF8 application. Ascorbic acid and its metabolites (dehydroascorbic acid, threonic acid, oxalic acid and xylose) were collected from human dermis by microdialysis and assessed by gas chromatography mass spectrometry. Irradiated site without sunscreen application had significantly demonstrated lower dermis ascorbic acid concentrations and a higher erythema index than the three other sites (P < 0.05). Threonic acid, oxalic acid and xylose dermis concentrations were significantly higher in site III than in the control site I (P < 0.05). The protected-irradiated site did not show erythema formation and there was stability of ascorbic acid dermis concentrations with non-variation in its metabolites. The assessment of ascorbic acid and its metabolites in human dermis could be an efficient tool to demonstrate the oxidative process and consequently to control the efficiency of sunscreen creams against undesirable UV effects.
Adult↗
Skin capillary network recognition and analysis by means of neural algorithms.
BACKGROUND: The intra-dermal capillary network can be easily assessed by a computerized videomicroscope system. Nevertheless, finding capillary loops automatically in an image is a difficult yet important first step in order to achieve microcirculation analysis. METHODS: A detection system was tested by combining videocapillaroscopy and principal component analysis (PCA). Our goal was to build a generic detector of capillary associated with a retinally connected neural network filter. The filter examines small windows of an image, and decides with this detector whether each window contains a capillary or not. RESULTS: Comparisons with manual detections showed that the system has a detection rate of 82% on test set A containing 100 good-quality images of the scalp. A detection rate of 65% was obtained on test set B containing 50 images with noisy background and large artifacts. The performance was increased by a color detector with a detection rate of 71% on the last test. These results correspond to a false detection rate lower than or equal to 10%. CONCLUSION: This neural filter system is capable of real-time processing; it recognizes capillaries anywhere in an image, and operates successfully under wide range of lighting and noisy conditions.
Algorithms↗
Comparison of fluorescence polarization immunoassay and high-performance liquid chromatography methods for assay of teicoplanin: can correlation be improved?
Teicoplanin is a glycopeptide indicated in serious infections due to Staphylococcus aureus and requires monitoring and dose adjustment based on measurement of trough concentration. Measurement of teicoplanin can be carried out by the fluorescence polarization immunoassay (FPIA) method or by high-performance liquid chromatography (HPLC) methods. We aimed to compare HPLC method using the sum of the peaks of A2-2, A2-3, A2-4 and A2-5 with FPIA method. Thirty-six serum samples obtained over a 6-month period from patients treated by teicoplanin were first analyzed by a HPLC method by determining both the A2-2 peak and the sum of areas of A2-2 to A2-5 and were then stored at -20 degrees C for FPIA assay. Correlation between FPIA and HPLC A2-2 methods was as: HPLC(A2-2) = 0.694FPIA - 0.892 with r(2) = 0.93. A paired t-test revealed significant differences between the results (P < 0.001). To improve the FPIA and HPLC correlation, we performed a linear regression between FPIA and the sum of A2-2, A2-3, A2-4 and A2-5 obtained in the HPLC method: HPLC(A2-2 to A2-5) = 0.953FPIA - 0.915 with r(2) = 0.96. A paired t-test did not show any significant difference between the results of the two methods (P = 0.94). These results show a better correlation between FPIA and HPLC when the sum of A2-2 to A2-5 was used for calculations. In conclusion, HPLC(A2-2 to A2-5) must be preferred to HPLC(A2-2) for the assay of teicoplanin, even if the HPLC(A2-2 to A2-5) runtime is higher than in the HPLC(A2-2) method.
Anti-Bacterial Agents↗
In vivo assessment of iron and ascorbic acid in psoriatic dermis.
Reactive oxygen species play an important role in inflammatory skin diseases such as psoriasis. Reactive oxygen species synthesis is catalysed by iron and some species are scavenged by ascorbic acid. The aim of this work was to assess iron and ascorbic acid in uninvolved and involved psoriatic dermis and to compare the corresponding concentrations in the dermis of healthy subjects. Microdialysis associated with atomic absorption spectrometry and gas chromatography-mass spectrometry was used to assess iron and ascorbic acid, respectively. Seven psoriatic patients and five healthy volunteers were studied. Iron concentrations in the involved (57.1 +/- 19.3 microg/l) and uninvolved (49.7 +/- 27.1 microgl/l) psoriatic dermis were higher than the corresponding value determined in the dermis of healthy subjects (21.8 +/- 2.4 microg/l) (p<0.05). Ascorbic acid in involved (47.3 +/- 8.2 microg/ml) and uninvolved (42.0 +/- 14.0 microg/ml) psoriatic dermis was statistically lower than that found in healthy dermis (176.8 +/- 29.0 microg/ml) (p<0.05). These results demonstrate that psoriatic patients exhibit high iron and low ascorbic acid concentrations in the dermis, but there were no significant differences between involved and uninvolved skin.
Adult↗
Thalidomide in patients with multiple myeloma and renal failure.
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Aged↗
[Management of a patient receiving thalidomide].
THE USE OF A DRUG WITH A TEMPORARY MARKETING AUTHORISATION: Thalidomide is currently available in France for nominative or cohort use with a temporary marketing authorisation (TMA). It is only prescribed and delivered in hospital settings. SIX OFFICIAL INDICATIONS: Its current indications are principally lepromatous nodular erythema, severe aphtosis, Jessner-Kanoff's cutaneous lymphocyte infiltration, discoid lupus erythematosis, chronic graft-versus-host reactions, and relapsed and or refractory multiple myeloma (after the failure of standard therapies). In the majority of cases, thalidomide is a last resort treatment of rare pathologies. On withdrawal, it is responsible for more or less long-term recurrences of the disease that require its re-introduction. SURVEILLANCE IS CRUCIAL: The side effects induced by thalidomide must never be forgotten, notably its teratogenic effects and its often irreversible neurotoxicity. The latter limit the long-term use of thalidomide and imply strict rules for its prescription and surveillance (efficient contraception, clinical neurological examinations, electroneurophysiological controls).
Abnormalities, Drug-Induced↗
High iron and low ascorbic acid concentrations in the dermis of atopic dermatitis patients.
BACKGROUND: Atopic dermatitis (AD) is a chronic inflammatory skin disease in which reactive oxygen species (ROS) may be involved. Iron catalyses ROS formation and ascorbic acid (AA) scavenges these species. OBJECTIVE: The aim of this work was to determine iron and AA levels in AD patients' dermis and to compare their concentrations with those of healthy volunteers' dermis. METHODS: Five AD patients and 5 healthy subjects (controls) were enrolled in this study. Iron and AA were collected from human dermis by microdialysis and assessed by atomic absorption spectrometry and gas chromatography-mass spectrometry, respectively. RESULTS: The AD dermis demonstrated higher iron concentrations (44.3 +/- 4.6 microg/l) compared to controls (21.8 +/- 1.2 microg/l) as well as a significantly lower concentration of AA (46.7 +/- 0.6 vs. 176.8 +/- 14.5 microg/ml, respectively). CONCLUSION: These results suggest that iron and AA dermis levels could be indicators of inflammatory tissues and might be implicated in dermatological diseases such as AD.
Adult↗
Validation of a microdialysis-gas chromatographic-mass spectrometric method to assess 8-methoxypsoralen in psoriatic patient dermis.
8-Methoxypsoralen (8-MOP) is currently used in PUVA therapy (psoralen+UVA) to treat dermatological diseases such as psoriasis, vitiligo and atopic dermatitis. The aim of this work was to validate a method for collecting 8-MOP from patient dermis by a non invasive technique, microdialysis, and then to assess this molecule by gas chromatography-mass spectrometry (GC-MS). 5-Methoxypsoralen (5-MOP) was used as an internal standard. The calibration curve demonstrated a linear relationship between the peak areas of 8-MOP and 5-MOP over a wide range of 8-MOP concentrations (0.9-100 ng/ml). Within- and between-run precisions were measured, using four different 8-MOP concentrations, which varied from 98.0 to 102.0% and from 98.5 to 101.8%, respectively. The limits of detection and quantification were 0.29 and 0.52 ng/ml, respectively. The method was validated and then applied to determine the pharmacokinetic of 8-MOP in ten psoriatic patient dermis, after oral intake of this drug. The results demonstrated that the association of microdialysis with the GC-MS method was an efficient procedure to collect and assess 8-MOP in human dermis, in vivo.
Adult↗
Ischaemic preconditioning and mast cell histamine release: microdialysis of isolated rat hearts.
The aim of this study was to investigate the feasibility of intramyocardium kinetics of histamine release by microdialysis in the isolated rat heart and ascertain if the inhibition of histamine release is implicated in the antiarrhythmic effect of preconditioning. A 30 min normothermic global ischaemia model followed by 30 min reperfusion was carried out in the control group (n= 9). In the preconditioning group (n= 8) there was a 5 min global ischaemia followed by 10 min of reperfusion. A mast cell stabilizing group received the disodium cromoglycate ( 10 micro M, n= 10). The last group received a mast cell degranulator, compound 48/80 (1micro g ml (-1), n= 10). In the control group, the histamine release during reperfusion was significantly different from the basal concentration ( 18.4 +/- 6.5 vs 1.9 +/- 0.5 nM, P< 0.05) and was associated with a maximal period of severe arrhythmias. The ischaemic preconditioning modified the histamine release kinetics with an early mast cell degranulation ( 9.7 +/- 1.5 nM) and a significant decrease in the total period of severe arrhythmias in comparison with the control group ( P< 0.05). In the disodium cromoglycate group, the histamine release during reperfusion decreased ( 3.1 +/- 0.7 nM) and was associated with a maximal period of severe arrhythmias. In the C48/80 group, the increase in the histamine released during reperfusion ( 21.2 +/- 5.0 nM) was associated with a maximal period of severe arrhythmias. These results showed firstly the feasibility of kinetic histamine release in myocardium interstitial fluid on the isolated rat heart and secondly that the inhibition of histamine release did not play a direct role in the antiarrhythmic effect of preconditioning.
Animals↗
Acitretin-associated thrombotic stroke.
OBJECTIVE: To report a case of thrombotic stroke. The etiology was difficult to identify, but was finally ascribed to psoriatic treatment with acitretin. CASE SUMMARY: Treatment with acitretin was prescribed for a 52-year-old white woman for long-standing psoriasis. Thirty-four days later, she developed nausea, vomiting, vertigo, and headaches, followed by left lateropulsion, which impeded standing and lying. Both neurologic examination and magnetic nuclear imaging indicated a rectangular infarct in the vermis cerebelli and a small bulbar infarct. Time-of-flight magnetic resonance angiography confirmed the presence of a thrombus at the beginning of the left vertebral artery. After heparin-based treatment and physiotherapy, the evolution was favorable. DISCUSSION: Etiology identification of the stroke included cardiogenic pathology and coagulopathy, but acitretin treatment was considered the likeliest explanation. On review of the literature, this seems to be the first case of a thrombotic event associated with acitretin. CONCLUSIONS: Acitretin should be considered as a possible cause of thrombotic stroke; this possibility should be kept in mind when patients taking acitretin develop an unexplained thrombotic event.
Acitretin↗
Iron and ascorbic acid concentrations in human dermis with regard to age and body sites.
BACKGROUND: Reactive oxygen species (ROS) contribute to processes relating to cutaneous aging. Iron catalyses ROS formation whereas ascorbic acid (AA) plays a fundamental role in defending the organism against undesirable ROS action. OBJECTIVE: The aim of this work was to determine the ex vivo iron and AA concentrations in human dermis from different age groups to better understand their role. METHODS: Skin fragments were collected from 66 female patients during surgical operations and were grouped according to age: group I (<15 years, before puberty, n = 12), group II (15-50 years, adults, n = 42), and group III (>50 years, advanced age adults, n = 12). Two sites were investigated: the abdomen (unexposed areas) and face (exposed sites). Iron and AA were collected from human dermis by microdialysis and assessed by atomic absorption spectrometry and gas chromatography mass spectrometry, respectively. RESULTS: Iron concentrations in the dermis were significantly higher in group III (27.4 +/- 20.9 microg/l) than in group I (13.8 +/- 3.3 microg/l; p< 0.05 ). An inverse correlation between AA dermis levels and increasing age was detected. For groups III and I, iron and AA concentrations were significantly different in dermis from the face compared to that of the abdomen (p < 0.05). CONCLUSION: This study shows for the first time that there is a direct relationship between iron and AA concentrations in the dermis and aging. Moreover, iron and AA concentrations differed according to body site.
Abdomen↗