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P Humbert

Publications and source records attributed to P Humbert.

At least 37 records · Page 2Linked to original sources
PubMed2003

Comparison of different wound dressings on cultured human fibroblasts and collagen lattices.

OBJECTIVE: We compared the effects on cultured human fibroblasts of a new non-adhesive wound dressing, Urgotul, with five other wound dressings. Urgotul is a hydrocolloid dressing; the comparator dressings included impregnated gauze and modern wound dressings. METHOD: Cultures in monolayer were used to study the morphology and growth of fibroblasts. The Bell model of cultured dermis equivalents was used to investigate myofibroblast differentiation. These cultures were labelled a-SM actin and F-actin. RESULTS: Two of the tested dressings induced cytotoxic effects. They were found to inhibit cell growth (greater than 60%) and to disturb cell shape and cytoskeletal differentiation. Urgotul and the remaining three dressings showed no effect on proliferation. However, some of them modified fibroblast morphology and affected F-actin distribution. CONCLUSION: Depending on their nature and components, wound dressings may respect or affect fibroblast behaviour in vitro (proliferation, morphology and a-SM actin and F-actin distribution). The significance of these in vitro observed findings require further investigations.

Actins↗
PubMed2003

[Severe acne].

Explore the source record for details and available documents.

Acne Vulgaris↗
PubMed2002

Assessment of collagen lattice thickness by B-scan echography.

BACKGROUND/AIMS: Collagen lattices are an in vitro dermal equivalent that has led to the development of an original model of dermal tissue. Fibroblasts cultured in three-dimensions in a collagen matrix differentiate similarly to in vivo. New technological performances in ultrasonic imaging can now provide precise measurements of tissue thickness with good resolution. The aim of this study was to assess, by B-scan echography, the correlation between collagen lattice thickness and various collagen and cell concentrations. METHODS: Three concentrations of human dermal fibroblasts (F1 = 8.10(5)C/mL, F2 = 16.10(5)C/mL, F3 = 32.10(5)C/mL) and three concentrations of rat tail collagen (C1 = 2 mg mL(-1), C2 = 3 mg mL(-1), C3 = 4 mg mL(-1)) were prepared for five different kinds of collagen lattices: F(2)C(1), F(2)C(2), F(2)C(3), F(1)C(1) and F(3)C(1) (n = 5 per case). Ultrasonic imaging was performed on day 0, 4, 6, 10, 12 and 14 using a Dermcup 2020 scanner. The scans measured thickness in the centre and periphery of the lattice. RESULTS: The collagen lattice echogenicity was similar to a dermis in vivo. For each assessment, the collagen lattice thickness increased until day 12 and then stabilized. The lattice was thicker when the cellular concentration was higher, (at day 14: F(1C1) = 0.66 mm, F(2C1) = 0.86 mm, F(3C1) = 1.21 mm). The collagen concentration did not significantly influence lattice thickness. CONCLUSION: Collagen lattice thickness increased with retraction time and cellular concentration.

Animals↗
PubMed2001

[Melanoma: role of ultraviolet radiation: from physiology to pathology].

EPIDEMIOLOGIC DATA: The frequency of malignant melanoma, by far the most fatal skin cancer, has increased by a factor of approximately 15 in the past 60 years. The factors underlying this rapid increase are incompletely understood, although ultraviolet radiations are likely strongly implicated. Epidemiologic studies demonstrate the role of altered patterns of sun exposure, and overexposition to UVA radiation, as confirmed by experimental data on animal models. BIOLOGICAL ASPECTS: Melanin produced by melanocytes has a photoprotective function in the skin, whereas UVB-induced DNA damage enhance the repair capacity of these cells. However, this photoprotective effect is not induced by intense intermittent sun exposure. In addition, melanocytes demonstrate resistance to UVB-induced apoptosis and are thus at high risk for incorporating UV-induced mutations. MOLECULAR ASPECTS: Different mutations in susceptibility genes (CDKN2A, INK4), or in genes implicated in control of cell cycle or maintenance of cell integrity (DNA repair) are involved in initiation and promotion steps of melanocarcinogenesis. Moreover, tumor progression is stimulated by UVB through the activation of different target genes that are implicated in control of melanoma environment (immune surveillance, angiogenesis, growth factors...).

Adolescent↗
PubMed2001

Optical analysis of displacement and strain fields on human skin.

BACKGROUND/AIMS: The aim of this article is to propose a new way to measure the mechanical behaviour of skin by using optical analysis software. Some examples on scars and stretch marks show the validity and the prospects of such a method. METHODS: Software is used to compare two states of deformation. The user takes two photos of the skin surface he wants to study, before and after the deformation is applied. The software is used to process the data. RESULTS: The software gives a mapping of the displacement, and strain fields of the area studied. Investigations can be realised in vitro or in vivo, and it is possible to study, for example, cutaneous lesions like scars and stretch marks. CONCLUSIONS: The method presented gives convincing results, which open many prospects in dermatology, surgery and cosmetology.

Cicatrix↗
PubMed2001

Topically applied vitamin C enhances the mRNA level of collagens I and III, their processing enzymes and tissue inhibitor of matrix metalloproteinase 1 in the human dermis.

Ascorbic acid (vitamin C) is a cofactor required for the function of several hydroxylases and monooxygenases. It is not synthesized in humans and some other animal species and has to be provided by diet or pharmacologic means. Its absence is responsible for scurvy, a condition related in its initial phases to a defective synthesis of collagen by the reduced function of prolylhydroxylase and production of collagen polypeptides lacking hydroxyproline, therefore, they are unable to assemble into stable triple-helical collagen molecules. In fibroblast cultures, vitamin C also stimulates collagen production by increasing the steady-state level of mRNA of collagen types I and III through enhanced transcription and prolonged half-life of the transcripts. The aim of the experimental work has been to evaluate the effect on dermal cells of a preparation of vitamin C topically applied on one side vs placebo on the other side of the dorsal face of the upper forearm of postmenopausal women. Biopsies were collected on both sides and the level of mRNA measured by non competitive reverse transcription-polymerase chain reaction made quantitative by the simultaneous transcription and amplification of synthetic RNA used as internal standards. The mRNA of collagen type I and type III were increased to a similar extent by vitamin C and that of three post-translational enzymes, the carboxy- and amino-procollagen proteinases and lysyloxidase similarly increased. The mRNA of decorin was also stimulated, but elastin, and fibrillin 1 and 2 were not modified by the vitamin. The expression of matrix metalloproteinases 1, 2, and 9 was not significantly changed, but an increased level of tissue inhibitor of matrix metalloproteinase 1 mRNA was observed without modification of tissue inhibitor of matrix metalloproteinase 2 mRNA. The stimulating activity of topical vitamin C was most conspicuous in the women with the lowest dietary intake of the vitamin and unrelated to the level of actinic damage. The results indicate that the functional activity of the dermal cells is not maximal in postmenopausal women and can be increased.

Administration, Topical↗
PubMed2001

Genital squamous cell carcinoma in men treated by photochemotherapy. A cancer registry-based study from 1978 to 1998.

BACKGROUND: One single report from the U.S. 16-centre-trial indicated that psoralen and ultraviolet A radiation (PUVA) therapy may induce an increased risk of genital tumours in men, and protection of the genital area is, therefore, recommended. OBJECTIVES: To evaluate the relevance of this risk in routine clinical practice. METHODS: Two groups of patients were included in a 1978-98 retrospective study. Case records of men with genital squamous cell carcinoma (SCC) identified from the Cancer Registry of the Doubs area of France were examined for a history of PUVA therapy, topical tar treatment, psoriasis, human papillomavirus infection or genital dermatitis. In addition, all the dermatologists of the Doubs area (in public and private practice) using PUVA therapy were asked to provide information on the number of patients having received PUVA therapy and whether the genital area was exposed during treatment. RESULTS: Between 1978 and 1998, among the 48 men who had developed a genital SCC in the Doubs area, only one had a history of intensive PUVA therapy. About 150,000 treatments with PUVA therapy had been performed by 15 dermatologists in the Doubs area for 5400 patients since 1978. No case of genital SCC had been reported, despite the fact that the genital area had not been protected during UVA exposure. CONCLUSIONS: Although retrospective, our study demonstrates that the occurrence of genital SCC in men treated with PUVA therapy is a very rare event in common dermatological practice.

Adult↗
PubMed2001

Assessment of the water content of the stratum corneum using a sorption-desorption test.

BACKGROUND/AIM: Various instruments based on electrical properties of the skin are currently used to assess the stratum corneum (SC) hydration state or water holding capacity. However, no direct relation with the quantity of water measured is provided. The objective of the present study was to calibrate the Corneometer, a device displaying electrical-capacitance-related values (which reflect the skin hydration state), and the amount and behaviour of the water taken up by the outer part of the SC during a sorption-desorption test. METHODS: The experiment was performed on the ventral forearms of 20 healthy volunteers after a rest in an environmentally controlled room. Corneometer and transepidermal water loss (TEWL) values were measured at intervals over the desorption process. The areas under the TEWL-versus-time curve provided the absolute amounts of residual sorbed water. RESULTS: The decrease kinetics of both signals after subtraction of prehydration values were very similar and bi-exponential, both showing a rapid, then a slower phase. The absolute amount of water taken up by the SC (hygroscopicity) and the two desorption rates were obtained. The Corneometer values were mono-exponentially related to the amount of water remaining within the SC. This allowed the in vivo calibration of the Corneometer in terms of absolute amount of water over the desorption range. CONCLUSION: The method may be used to calibrate in vivo other electrical devices aimed at assessing SC hydration during a sorption-desorption test. It may also provide new ways to measure SC water uptake and water holding capacity following application of products.

Absorption↗
PubMed2001

Multicenter randomized comparative double-blind controlled clinical trial of the safety and efficacy of zinc gluconate versus minocycline hydrochloride in the treatment of inflammatory acne vulgaris.

BACKGROUND: In addition to tetracyclines, zinc may constitute an alternative treatment in inflammatory lesions of acne. OBJECTIVE: To evaluate the place of zinc gluconate in relation to antibiotics in the treatment of acne vulgaris. METHODS: Zinc was compared to minocycline in a multicenter randomized double-blind trial. 332 patients received either 30 mg elemental zinc or 100 mg minocycline over 3 months. The primary endpoint was defined as the percentage of the clinical success rate on day 90 (i.e. more than 2/3 decrease in inflammatory lesions, i.e. papules and pustules). RESULTS: This clinical success rate was 31.2% for zinc and 63.4% for minocycline. Minocycline nevertheless showed a 9% superiority in action at 1 month and one of 17% at 3 months, with respect to the mean change in lesion count. Regarding safety, the majority of the adverse effects of zinc gluconate and of minocycline concerned the gastrointestinal system and were moderate (5 dropouts with zinc gluconate and 4 with minocycline). CONCLUSION: Minocycline and zinc gluconate are both effective in the treatment of inflammatory acne, but minocycline has a superior effect evaluated to be 17% in our study.

Abdominal Pain↗
PubMed2001

Iron concentrations in human dermis assessed by microdialysis associated with atomic absorption spectrometry.

Until recently, the determination of metallic elements concentrations in normal skin, in vivo, was rare due to the lack of non-invasive techniques. Microdialysis has the advantage of being slightly invasive when applied to the collection in vivo of endogenous or exogenous substances from the skin. Iron is an active element in different cutaneous disorders. The aim of this work was to assess iron by atomic absorption spectrometry (AAS) after the collection of samples by microdialysis from human dermis. A first essential step, before determining the in vivo iron concentration in human dermis, was to establish an experimental protocol applicable to ex vivo as well as in vivo conditions. For this reason, this work deals only with the assessment of iron in ex vivo human dermis. A skin microdialysis technique and a calibration method, the No Net Flux, were used to quantify basal iron concentrations in human dermis and the same method was also used to determine in vitro and ex vivo iron recoveries. No differences were detected between in vitro and ex vivo recoveries. Ex vivo basal iron dermis concentrations ranged from 3.6 to 7.7 microg/l. This study shows that non-invasive microdialysis is an efficient method for sampling iron from human skin. A sensitive and accurate AAS technique was able to assess low iron concentrations in human dermis. The strategy adopted for this work was efficient and appropriate for the determination of iron in human skin and experiments will be carried out in vivo.

Dermis↗
PubMed2001

[Surgical treatment of Verneuil's disease (hidradenitis suppurativa): 15 cases].

INTRODUCTION: Verneuil's disease (hidradenitis suppurativa) is a chronic inflammatory, suppurating and fistulizing disease of apocrine sweat gland-bearing skin. The aim of this study was to describe the surgical treatment, conducted in 15 patients suffering from this disease. PATIENTS AND METHODS: We retrospectively analyzed 15 observations (9 men, 6 women, mean age 38.6). The mean delay between beginning of the symptoms and diagnosis was 55.5 months. Surgery was conducted at the stage of abscesses, fistulization and keloids in all patients. The first surgical step was wide and deep excision of affected skin and subcutaneous fat. The second step was secondary intention healing, or ideal suture, Z plasty or dorsalis major flap. RESULTS: Only four patients had complications: two axillary strictures, one anal margin stenosis and one hypertrophic scarring. Three relapses occurred, treated by excision under local anesthesia. CONCLUSION: Surgical treatment seems to be the only definitive treatment of Verneuil's disease.

Abscess↗
PubMed2001

[Mechanical behavior of fibroblasts included in collagen lattices].

Striae distensae are characterized by linear, smooth bands of atrophic-appearing skin. Excessive steroid activity, genetic and mechanical factors and inherited defects of connective tissues are the most frequent causes of this disease. Fibroblasts derived from women presenting striae distensae lesions were included into collagen gels to study their mechanical behavior: capacity to contract free-floating lattices and to produce isometric force in tense lattices. To measure the retracted lattice diameter, the culture dishes were placed on a transparent metric scale. An isometric force system was used to study quantitatively the forces developed during lattice contraction. alpha 2 beta 1 integrins expression (transmembrane receptors) was evaluated by flux cytometry. Striae distensae fibroblasts contract collagen gels slower than normal human fibroblasts but the final contraction is similar. They produce a greater isometric force which is associated with enhanced alpha 2 beta 1 integrins expression. By their mechanical properties, striae distensae fibroblasts appear as a different population from normal fibroblasts.

Adult↗
PubMed2000

[Nail manifestations of systemic diseases].

General diseases-associated nail disorders may be classified into 5 types according to their clinical impact. Type I refers to nail disorders considered as peculiar features among the various symptoms of general disease such as peri-ungueal vascular dilatation, onycholysis, Beau lines, opaque nails or melanonychia. Type II refers to nail disorders with a strong clinical value such as Terry's nails, Muerhrcke's lines or koilonychia. Type III refers to nails disorders presenting as significant syndromes of several diseases such as yellow-nail syndrome of subungueal splinter haemorrhages, and type IV to specific disorders considered as true keys for diagnosis such as digital hippocratism, Bazex's acrokeratosis, Koenen's tumor, or nail hypoplasia. In type V are included drug-induced nails disorders especially after chemiotherapy or antiretroviral therapy.

Autoimmune Diseases↗
PubMed2000

Extensive vitiligo after ganciclovir treatment of GvHD in a patient who had received donor T cells expressing herpes simplex virus thymidine kinase.

The use of donor T cells expressing a suicide gene for destruction of graft-versus-host effector cells provides a tool for alloreactivity modulation. We describe a case of extensive vitiligo that developed after ganciclovir treatment of cutaneous chronic graft-versus-host disease in a patient who had received donor T lymphocytes expressing herpes simplex virus thymidine kinase at the time of transplantation.

Adult↗
PubMed2000

Skin manifestations associated with toxocariasis: a case-control study.

BACKGROUND: Human toxocariasis is one of the most common zoonotic helminthiases. The recent development of sensitive and specific diagnostic laboratory tests has led to identify a large spectrum of diseases, including cutaneous diseases, induced by Toxocara infection. OBJECTIVE: The purpose of our study was to assess the risk of having a positive Toxocara ELISA test in patients with different cutaneous symptoms. METHODS: The diagnosis of toxocariasis was based on an ELISA test which was performed in 653 patients suffering from different skin conditions during a prospective case-control study. RESULTS: The excess of risk (adjusted odds ratio) of having a positive result in the Toxocara ELISA was statistically significant for 134 patients with urticaria (whatever the clinical presentation) and for 22 patients with prurigo compared to a control group (249 patients). No statistical excess of risk was observed for patients with atopic dermatitis, pruritus or non-atopic eczema. CONCLUSION: The authors conclude that patients suffering from urticaria or prurigo should be tested for Toxocara infection. Whether these patients should be treated with anthelminthic drugs remains to be determined in further studies.

Adolescent↗
PubMed2000

The detection of tyrosinase mRNA in the peripheral blood of stage I melanoma patients is not of clinical relevance in predicting metastasis risk and survival.

The presence of tyrosinase mRNA in the peripheral blood cells of melanoma patients has been recently studied as a possible marker of haematogenous dissemination. However, considerable variations in the rates of detection have been noted. We determined the presence of tyrosinase mRNA-positive circulating cells using reverse transcriptase-polymerase chain reaction (RT-PCR) in 35 patients with stage I melanoma, two patients with stage II melanoma and two patients with stage III melanoma. Among the patients with stage 1, 13 were tested before and after surgery (< 1 h). Twenty healthy subjects served as negative controls. Out of the melanoma patients, the tyrosinase gene was expressed in three of the 52 samples tested. Tyrosinase mRNA was present in the circulating cells of only one patient with stage I melanoma after intra-congenital naevi resection. However, two other stage I patients developed rapidly lethal metastasis within the following 6 months, despite the lack of detectable tyrosinase mRNA. None of stage II patients were positive for the tyrosinase transcripts, while both patients with stage III melanoma showed enzyme expression. Our results confirm those of previous studies, showing that a small proportion of stage I melanoma patients have tyrosinase-positive circulating cells. Moreover, the lack of tyrosinase mRNA detection in the blood does not necessarily exclude metastatic progression. Therefore, this study indicates that the detection of tyrosinase mRNA-positive circulating cells by RT-PCR is not a predictive biomarker of a metastasis risk in patients with stage I melanoma.

Biomarkers, Tumor↗
PubMed2000

[Descriptive epidemiological study of acne on scholar pupils in France during autumn 1996].

BACKGROUND: Acne is the most common symptom prompting patients to consult a dermatologist. No previous study has been conducted in France to determine the prevalence of acne and describe the main epidemiological features. SUBJECTS AND METHODS: A cross sectional study was conducted in November 1996 and included 913 school children aged 11 to 18 years. This sample was statistically representative of the entire secondary school population in France during the 1996-1997 school year. The subjects were stratified by 5 criteria: age, sex, rural or urban residence, sun exposure, type of school. RESULTS: Taking the clinical diagnosis made by the dermatologist investigator as the main criteria, the overall prevalence of acne was 72 p. 100. It was 76.1 p. 100 using the new ECLA grading system previously described. The prevalence of acne was sex and age dependent: highest scores were found for girls aged 14-16 years and for boys aged 16-17 years. Genetic factors were very important for the outcome of acne. Finally, 41 p. 100 of the acneic subjects were following a treatment, prescribed by a dermatologist in two-third of the cases. DISCUSSION: These results are in agreement with those previously published in the literature although some differences were disclosed. It would appear important to distinguish between minimal acne with a few retentional pimples occuring during adolescence and severe acne (more than 20 pimples on the face) requiring early medical care to avoid scarring.

Acne Vulgaris↗