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P Bastien

Publications and source records attributed to P Bastien.

At least 19 recordsLinked to original sources
PubMed2007

In vitro and in vivo confocal Raman study of human skin hydration: assessment of a new moisturizing agent, pMPC.

The hydration capacities of a biomimetic polymer, 2-methacryloyloxethylphosphorylcholine polymer (pMPC), alone and microencapsulated, in association with another well known hydrating polymer, Hyaluronic acid, were investigated in vitro on skin models and in vivo on volunteers by using confocal Raman microspectroscopy. The hydration impact and the relative water content in the Stratum corneum were calculated from the Raman spectra using the OH (water)/CH3 (protein) ratio. Moreover, the follow-up of the presence of pMPC through the Stratum corneum was possible with confocal Raman microspectroscopy, using a characteristic vibration of pMPC, different from that of the encapsulating material. From our in vitro measurements, the improved hydration of the Stratum corneum was confirmed by the use of the encapsulated form of pMPC, which was higher when combined with Hyaluronic acid. On the basis of these in vitro findings, we validated this trend in in vivo measurements on 26 volunteers, and found a good correlation with the in vitro results. Mechanical and ultrastructural studies have been carried out to demonstrate the positive effects of the pMPC on the Stratum corneum function, namely the interaction with lamellar lipids and the plasticizing effects, which are both supposed to spell out the moisturizing effect. This study demonstrates the efficiency of a original hydrating agent, pMPC, entrapped with Hyaluronic acid in a new type of microcapsules by the use of a novel tool developed for both in vitro and in vivo approaches. This indicates a new step to evaluate and improve new moisturizers in response to the cosmetics or dermatologic demands.

Adult↗
PubMed2006

An in vivo randomized study of human skin moisturization by a new confocal Raman fiber-optic microprobe: assessment of a glycerol-based hydration cream.

BACKGROUND: In a recent study, we demonstrated the ability of the new confocal Raman microprobe to investigate molecular and structural human skin composition under in vivo conditions. Experiments were performed at different anatomical sites, different layers, and with intervolunteer comparison. We also carried out feasibility tests using this probe to determine depth profiles of water content within the skin. OBJECTIVE: In the present investigation we employed this confocal Raman optical microprobe to rigorously objectify the resulting hydration capacities after application of a moisturizing enhancer. METHOD: The in vivo experiments were performed on 26 healthy volunteers and measurements were undertaken on six areas of the volar forearm after a randomized application of hydrating agents. Responses were evaluated by calculating the water/protein band ratio, which determines the water content in the skin. RESULTS: Data collected with the Raman microprobe showed significant changes between baseline values of control and treated skins. Statistical analysis performed on these data revealed an increase in skin moisture after application of a glycerol-based cream, which is the most widely used hydrating agent. CONCLUSION: Our results demonstrate clearly the potentials of this confocal Raman microprobe in the screening of hydrating agents or molecules under in vivo conditions. In the cosmetics field, this promising and suitable technique will undoubtedly offer new opportunities of hydration skin test evaluation.

Administration, Cutaneous↗
PubMed2005

Skin ageing: a comparison between Chinese and European populations. A pilot study.

BACKGROUND: Although limited data are available, it is commonly considered that Europeans and Asians have different skin ageing features. OBJECTIVES: The present studies have been carried out to evaluate the influence of age and sun-exposure on the main clinical signs of Asian skin ageing. METHODS: One hundred and sixty Chinese and 160 French age-matched women (age range: 20-60 years old) were clinically examined and scored by the same dermatologist. Facial wrinkles (crow's-feet, glabella and perioral wrinkles) and pigmented spots (on face and hands) were assessed in situ and standardized photographs of the face were taken. Lifelong sun-exposure was estimated from answers to a questionnaire. Comparisons were made between 10-year age groups. RESULTS: Results show that, for each facial skin area, wrinkle onset is delayed by about 10 years in Chinese women as compared to French women. Facial wrinkling rate over the years is linear in French women and not linear in Chinese women who appear to experience a fast ageing process between age 40 and 50. Pigmented spot intensity is a much more important ageing sign in Chinese women (severe for 30% of women over 40) than in French women (severe for less than 8% of women, irrespective of age). CONCLUSION: These first results underline that main skin ageing features (wrinkles, spots) progress differently in the Chinese and French women we have studied. They require to be confirmed on broad multicentre studies involving larger cohorts.

Adult↗
PubMed2005

Usefulness of PCR in the diagnosis of cutaneous leishmaniasis in Tunisia.

We assessed the efficiency of a PCR method in establishing the diagnosis of cutaneous leishmaniasis (CL) in Tunisian patients. Four hundred and thirty specimens collected passively from patients with cutaneous ulcers suggestive of leishmaniasis attending health centres for diagnosis were included in the study. Dermal scrapings were analysed both by parasitological (examination of Giemsa-stained smears and in vitro cultivation) methods and by a genus-specific PCR detecting a fragment of the 18S rRNA gene. Microscopy revealed amastigotes in 245 samples (57.0%) and in vitro cultivation gave positive results in 88 cases (20.5%), whereas PCR detected Leishmania in 301 samples (70%). The sensitivities inferred from our results were 99.3%, 80.8% and 29% for PCR, microscopic examination and in vitro cultivation, respectively. The different forms of CL in this country are caused by three species of Leishmania and are treated with the same protocol. Of 303 well-documented cases in our study, 99% were probably caused by Leishmania major and 1% by Leishmania infantum. The lack of species-specific diagnosis is not known to affect treatment or prognosis in Tunisia. These data support the incorporation of PCR into diagnostic strategies for CL, particularly in Tunisia.

Animals↗
PubMed2004

In vivo epidermal thickness measurement: ultrasound vs. confocal imaging.

BACKGROUND/PURPOSE: In this study, in vivo skin imaging methods, ultrasound (US) and confocal microscopy (CM) were compared with regards to their accuracy in measuring the epidermal thickness. In addition an attempt was made to clarify the biological significance of the second echo-rich line observed on US skin images, i.e. whether it represents the dermal-epidermal junction or the papillar-reticular dermis limit. METHODS: US images were obtained with an in-house device (22 MHz probe) and the CM images with the VivaScope 1000 (Lucid Inc., Rochester, NY, USA). Skin from the dorsal forearm, the back of hand and the palm skin of 11 subjects (25-40 years) were examined. Repeatability of the procedure and reproducibility of the results were evaluated on repeated measurements taken at 1-month interval. RESULTS: Both techniques are correlated. When a CM measurement is performed from the stratum corneum (SC) surface to the bottom of the papillae, results obtained with US and CM are very similar. Thus, the second echo-rich line on US skin imaging is likely to reflect a virtual line joining the bottom of the papillae. CM is limited to the measurement of a relative thin epidermis, due to the signal-to-noise ratio, which decreases with depth. US technique offers a better repeatability and reproducibility, particularly for SC measurement. This is mainly due to the small size of the investigated field of view in CM. CONCLUSIONS: This study confirms the accuracy of US and the feasibility of CM imaging techniques for in vivo epidermal thickness measurement. Echography probably measures a maximal epidermal thickness since it encompasses the bottom of the papillae.

Adult↗
PubMed2002

Value of two PCR methods for the diagnosis of canine visceral leishmaniasis and the detection of asymptomatic carriers.

The value of 2 PCR methods, targeting genomic and kinetoplast minicircle DNA respectively, was investigated for both diagnosis and prevalence studies of canine visceral leishmaniasis (CVL). The first method (R) was 5000-fold less sensitive than the second (method KRV). Both were tested for diagnosis of CVL in 44 sick dogs with confirmed disease using different biological samples. Method R was highly efficient when using invasive samples, but the use of method KRV proved necessary for a 100% sensitive diagnosis using peripheral blood. This method was applied to peripheral blood and skin samples in 263 dogs during a mass survey in the Cévennes focus. PCR was compared to serology and all results were analysed according to clinical status. The 'CVL-infection' prevalence was found to be 79.8% by PCR compared with 29.6% by serology: 89.4% of symptomatic and 65.2% of asymptomatic dogs harboured parasites in peripheral blood. This study confirms the high prevalence of asymptomatic carriers of Leishmania. In total, for the diagnosis of CVL in sick dogs, method R is recommended in view of its 100% positive predictive value (compared with 30% for method KRV). A strategy best adapted for prevalence surveys might combine serology and highly sensitive PCR on peripheral blood.

Animals↗
PubMed2002

Ethnic variations in self-perceived sensitive skin: epidemiological survey.

To examine possible ethnic variations in perception of sensitive skin, an epidemiological survey was performed in the San Francisco area. Approximately 800 telephone interviews were conducted with women from four different ethnic groups (Afro-Americans, Asians, Euro-Americans, Hispanics; approximately 200 women per group). In addition to sensitive facial skin assessments, age and other general skin condition data were collected. 52% of the subjects identified themselves as having sensitive facial skin. There was no statistical difference between the ethnic groups in terms of sensitive skin prevalence. Nevertheless, some differences were noted between ethnic subgroups of sensitive skin. Euro-Americans were characterized by a higher skin reactivity to wind and tended to be less reactive to cosmetics. Afro-Americans presented diminished skin reactivity to most environmental factors and a lower frequency of recurring facial redness. Asians appeared to have greater skin reactivity to spicy food, to sudden changes in temperature and to wind, and tended to suffer from itching more frequently. Hispanics presented a lower incidence of skin reactivity to alcohol. The differences in skin sensitivity between ethnic groups concerned mostly factors of skin reactivity and, to a lesser extent, its symptomatology. But, taken together, we note the similarities in comparing how women of varying ethnic backgrounds perceive the sensitive skin condition.

Adolescent↗
PubMed2001

Effect of large targeted deletions on the mitotic stability of an extra chromosome mediating drug resistance in Leishmania.

A mitotically stable linear extra chromosome obtained in a Leishmania donovani strain rendered mycophenolic acid-resistant has been physically mapped. This 290-kb chromosome has an inverted duplicated structure around a central inversion region, and is derived from a conservative amplification event of a approximately 140-kb subtelomeric end of chromosome 19. Large-sized targeted deletions of the central region were performed through homologous recombination using three specific transfection vectors. The size of the extra chromosome was thus successfully reduced from 290 to 260, 200 and 120 kb respectively. The mitotic stability of these chromosomes was then analysed in drug-free cultures over >140 days. Results differed according to the deletion created. By contrast with the smallest deletion the two largest deletions altered mitotic stability, leading to progressive loss of the size-reduced chromosomes with similar kinetics in both mutants. The 30-kb region common to both deletions may therefore be considered as involved in mitotic stability. A 44-kb contig covering this region could be assembled and sequenced. The analysis of this sequence did not reveal any sequence elements typical of centromeric DNA. By contrast, its enrichment in homopolymer tracts suggests that this region might contain an origin of replication.

Animals↗
PubMed2001

Statistical analysis of regulatory ecotoxicity tests.

ANOVA-type data analysis, i.e.. determination of lowest-observed-effect concentrations (LOECs), and no-observed-effect concentrations (NOECs), has been widely used for statistical analysis of chronic ecotoxicity data. However, it is more and more criticised for several reasons, among which the most important is probably the fact that the NOEC depends on the choice of test concentrations and number of replications and rewards poor experiments, i.e., high variability, with high NOEC values. Thus, a recent OECD workshop concluded that the use of the NOEC should be phased out and that a regression-based estimation procedure should be used. Following this workshop, a working group was established at the French level between government, academia and industry representatives. Twenty-seven sets of chronic data (algae, daphnia, fish) were collected and analysed by ANOVA and regression procedures. Several regression models were compared and relations between NOECs and ECx, for different values of x, were established in order to find an alternative summary parameter to the NOEC. Biological arguments are scarce to help in defining a negligible level of effect x for the ECx. With regard to their use in the risk assessment procedures, a convenient methodology would be to choose x so that ECx are on average similar to the present NOEC. This would lead to no major change in the risk assessment procedure. However, experimental data show that the ECx depend on the regression models and that their accuracy decreases in the low effect zone. This disadvantage could probably be reduced by adapting existing experimental protocols but it could mean more experimental effort and higher cost. ECx (derived with existing test guidelines, e.g., regarding the number of replicates) whose lowest bounds of the confidence interval are on average similar to present NOEC would improve this approach by a priori encouraging more precise experiments. However, narrow confidence intervals are not only linked to good experimental practices, but also depend on the distance between the best model fit and experimental data. At least, these approaches still use the NOEC as a reference although this reference is statistically not correct. On the contrary, EC50 are the most precise values to estimate on a concentration response curve, but they are clearly different from the NOEC and their use would require a modification of existing assessment factors.

Animals↗
PubMed2001

A unique surface membrane anchored purine-salvage enzyme is conserved among a group of primitive eukaryotic human pathogens.

Previously, we isolated and characterized the gene encoding the 3'-Nucleotidase/Nuclease (Ld3'NT/NU) from the human pathogen, Leishmania donovani. This unique cell surface enzyme has been shown to be involved in the salvage of host-derived purines, which are essential for the survival of this important protozoan parasite. In this report, we assessed whether the 3'-Nucleotidase/Nuclease was conserved amongst other pathogenic Leishmania and related trypanosomatid parasites. Results of pulsed field gel electrophoresis and Southern blotting showed that a Ld3'NT/NU gene homolog was present in each of the visceral and cutaneous Leishmania species tested (i.e. isolates of L. donovani, L. infantum, L. tropica, L. major and L. mexicana, respectively). Further, results of colorimetric assays using 3'-adenosine monophosphate as substrate demonstrated that each of these organisms also expressed significant levels of 3'-nucleotidase enzyme activity. In addition, we showed that a Ld3'NT/NU gene homolog was expressed in each of these Leishmania species as a > 40 kDa 3'-nucleotidase enzyme activity. A Ld3'NT/NU gene homolog was also identified in two Crithidia species (C. fasciculata and C. luciliae) and Leptomonas seymouri but was only marginally detectable in Trypanosoma brucei, Trypanosoma cruzi and Phytomonas serpens. Cumulatively, results of this study showed that an Ld3'NT/NU homolog was conserved amongst pathogenic Leishmania sp. which suggests that this enzyme must play an critical role in purine salvage for all members of this group of human pathogens.

Animals↗
PubMed2001

Sensitive skin: an epidemiological study.

BACKGROUND: There is a growing awareness that some individuals exhibit heightened skin sensitivity, particularly on the face, and have a high incidence of adverse reactions to cosmetics and toiletries. OBJECTIVES: To carry out an epidemiological study to assess the prevalence of sensitive skin and cosmetic-related adverse events in a U.K. population, and to examine possible factors that may be associated with sensitive skin. METHODS: Self-assessment questionnaires were sent out to 3300 women and 500 men, randomly selected, who were over the age of 18 years and lived within a 10-mile radius of High Wycombe (Bucks.). Fifty non-responder women were also questioned by telephone to ensure that the postal responders were representative of the population as a whole. RESULTS: The response rates were 62% for women and 52% for men, with the incidence of self-reported skin sensitivity being 51.4% and 38.2%, respectively. Ten per cent of women and 5.8% of men described themselves as having very sensitive skin. Fifty-seven per cent of women and 31.4% of men had experienced an adverse reaction to a personal product at some stage in their lives, with 23% of women and 13.8% of men having had a problem in the last 12 months. Among the women, symptoms of cosmetic-induced subjective sensory skin discomfort (burning, stinging, itching etc.) occurred more commonly in the sensitive skin cohort (53%) than in those who regarded themselves as non-sensitive (17%). An atopic diathesis in women did not appear to be a predictive factor for sensitive skin, the incidence of self-perceived sensitive skin being equivalent for atopics (49%) and non-atopics (51%). Furthermore, some 34% of atopic women described themselves as being non-sensitive. Nevertheless, the incidence of atopy was higher among the women in the sensitive skin group (49%) than among those in the non-sensitive group (27%). Dry skin and a predilection for blushing/flushing were associated factors for sensitive skin. CONCLUSIONS: Our survey indicates that sensitive facial skin is a common problem for women and men in the U.K. and points to the need for the development of personal products designed for this skin phenotype.

Adult↗
PubMed2001

Comparison of various sample preparation methods for PCR diagnosis of visceral leishmaniasis using peripheral blood.

We have compared various sample preparation methods for the PCR diagnosis of visceral leishmaniasis (VL) using peripheral blood samples and tested the influence of these protocols upon sensitivity. Four methods of lysis-DNA extraction were used with two types of blood samples: whole blood (WB) and buffy coat (BC). Comparisons were first carried out with seeded samples at various parasite concentrations. At high concentrations (> or = 1,000 parasites/ml), there were no significant differences in PCR sensitivity among the methods tested. At concentrations of < or = 100 parasites/ml, proteinase K (PK)-based methods proved clearly superior to guanidine-EDTA-based methods. Moreover, a 10-fold increase in sensitivity was observed for BC over that for WB. Thus, the best sensitivity was obtained with the BC prepared with PK-based methods. With this combination, the PCR reliably detected 10 parasites/ml but was inconsistent when the sample contained 1 parasite/ml of blood. The methods that yielded the highest sensitivities were evaluated with seven dogs and four human VL patients. Again, the utilization of the BC prepared with PK-based methods gave the best results. The optimization of each step of the assay (sample preparation, DNA extraction, and PCR conditions) yielded a highly sensitive tool for the diagnosis of VL using patient blood, thus avoiding more invasive diagnostic procedures and allowing the detection of low parasitemia during posttherapeutic follow-up.

Animals↗
PubMed2001

Hair diameter diversity: a clinical sign reflecting the follicle miniaturization.

BACKGROUND: The degree of androgenetic alopecia is generally evaluated either by global clinical scales or time-consuming methods like phototrichogram or histological studies. We describe a new clinical and reliable scoring method based on hair diameter diversity. OBSERVATIONS: (1) The clinical macroscopic scoring we propose for hair density was significantly correlated with Hamilton classification and with histological hair density. (2) Diversity in hair diameter was the main and most accurate clinical parameter linked to follicle miniaturization. (C) The anagen-telogen ratio decreased in parallel with the decrease in clinical hair density score. CONCLUSIONS: Considering that hair follicle miniaturization is the key point during androgenic alopecia onset and development, diversity in hair diameter represents an important feature to consider as an accurate clinical sign reflecting hair follicle miniaturization. Moreover, diversity in hair diameter seems to be an easily accessible and reliable parameter that should be taken into consideration for further characterization of hair disorders. By itself, we believe that this clinical feature constitutes a new tool of substantial help for the diagnosis and management of androgenic alopecia.

Adult↗
PubMed2000

Optimized PCR using patient blood samples for diagnosis and follow-up of visceral Leishmaniasis, with special reference to AIDS patients.

We developed a highly sensitive PCR method that enables the diagnosis and posttherapeutic follow-up of visceral leishmaniasis with patient blood. The PCR assay was thoroughly optimized by successive procedural refinements to increase its sensitivity and specificity. It was compared to in vitro cultivation as well as to direct examination of bone marrow and to serology. Two hundred thirty-seven patients presenting with clinical signs compatible with visceral leishmaniasis were included in the study. Thirty-six were diagnosed as having Mediterranean visceral leishmaniasis (MVL). Twenty-three of them, including 19 AIDS patients, were monitored during and after treatment over a period from 2 weeks to 3 years. Our PCR assay proved more sensitive than in vitro cultivation, direct examination, and serology for all patients. It is simple and can be adapted to routine hospital diagnostic procedures. For the primary diagnosis of MVL, the sensitivity of PCR versus that of cultivation was 97 versus 55% with peripheral blood and 100 versus 81% with bone marrow samples. Regarding posttherapeutic follow-up, overall, 48% of positive samples were detected by PCR only. Seven patients presented with a clinical relapse during the study; six relapses were detected at first by PCR only, sometimes a few weeks before the reappearance of signs or symptoms. We conclude that an optimized and well-mastered PCR assay with a peripheral blood sample is sufficient to provide a secure diagnosis for all immunocompromised patients and most immunocompetent patients. We also suggest systematic posttherapeutic monitoring by PCR with peripheral blood for immunocompromised patients.

Acquired Immunodeficiency Syndrome↗
PubMed1999

High conservation of the fine-scale organisation of chromosome 5 between two pathogenic Leishmania species.

In a previous work we showed a remarkable conservation of the general structure of the genome (chromo-some number and synteny) among different pathogenic species of Old World Leishmania, indicating the absence of major interchromosomal rearrangements during evolution. In the present study, we have compared the fine structure of chromo-some 5 among two of these divergent species (Leishmania major and Leishmania infantum) by means of physical mapping. Remarkably, the 42 markers jointly mapped on these two chromosomes were found in an identical order along the chromosome. This perfect colinearity of the markers is in striking contrast to the large genetic distance that separates these species and suggests that conservation of the fine-scale organisation of chromosomes may be critical in Leishmania. If this colinearity is confirmed on the whole of the chromosome set, the current systematic sequencing programme of the genome of L.major should greatly help in the development of comparative genetics between different species of Leishmania.

Animals↗
PubMed1999

Leishmania major Friedlin chromosome 1 has an unusual distribution of protein-coding genes.

Leishmania are evolutionarily ancient protozoans (Kinetoplastidae) and important human pathogens that cause a spectrum of diseases ranging from the asymptomatic to the lethal. The Leishmania genome is relatively small [ approximately 34 megabases (Mb)], lacks substantial repetitive DNA, and is distributed among 36 chromosomes pairs ranging in size from 0.3 Mb to 2.5 Mb, making it a useful candidate for complete genome sequence determination. We report here the nucleotide sequence of the smallest chromosome, chr1. The sequence of chr1 has a 257-kilobase region that is densely packed with 79 protein-coding genes. This region is flanked by telomeric and subtelomeric repetitive elements that vary in number and content among the chr1 homologs, resulting in an approximately 27.5-kilobase size difference. Strikingly, the first 29 genes are all encoded on one DNA strand, whereas the remaining 50 genes are encoded on the opposite strand. Based on the gene density of chr1, we predict a total of approximately 9,800 genes in Leishmania, of which 40% may encode unknown proteins.

Animals↗