[Sun exposure at school: Evaluation of risk (erythema dose), benefits (vitamin-D synthesis) and behaviour among children in France]. / Exposition solaire en milieu scolaire : évaluation du risque (dose érythémale), du bénéfice (synthèse de vitamine D) et des comportements des enfants.

BACKGROUND: To better understand the potential risk associated with sun exposure during the school year, we decided to evaluate behaviour, risk [UV index (UVI), minimal erythema dose (MED)] and benefits (vitamin-D synthesis) of sun exposure in primary schoolchildren in France, as well as the various sun protection methods used for children. MATERIAL AND METHODS: We performed the study on a sunny day (July 24) in a school in Antony (France). Evaluation of UVI (with calculation of MED) and the amount of vitamin D synthesized according to exposed body surface area and phototype were performed every 15minutes from 9 a.m. to 5 p.m. The effects of albedo and shade on UVI were assessed in 8 different locations at the school. The sun-protection measures used by the children were systematically evaluated. RESULTS: Fifty-seven children were evaluated; the maximum UVI was 7.2 and the maximum temperature was 30.7°C. Irrespective of phototype and clothing, 1 MED was reached and an adequate level of vitamin D was synthesized in the skin before midday. Albedo had little impact on irradiation. The amount of protection afforded by shadow varied greatly, with the highest level occurring in the covered courtyard (99.5% reduction of UVI) and the lowest in the shadow of buildings (53.7% reduction of UVI). With strict sun protection measures concerning dress, children reached 1 MED before synthesizing 1000IU of vitamin D, but with clothing "suited to high temperatures", 1000IU of vitamin D were synthetized before 1 MED was reached. Compliance with photoprotection measures was poor. Regardless of duration of exposure during the day (minimal model: two play breaks+lunchtime break) and of skin phototype, at least 1.5 MED was reached during the day. STUDY LIMITATIONS: This was an experimental study ignoring children's actual behaviour (movement, sweating, application of sun protection products, etc.). Moreover, due to weather conditions, the study was performed at a recreation centre in July and not during the "standard" school year. CONCLUSION: Sun protection campaigns should naturally be directed chiefly towards children for several reasons relating to solar risk and learning. This study shows the complex link between UV, MED, vitamin D as well as the difficulties of implementing solar protection measures in schools in France.

French teenagers and artificial tanning.

BACKGROUND: Exposure to solar and artificial ultraviolet (UV) radiations is a major risk factor for skin cancers. France has enacted one of the strictest laws that, notably, restrict tanning-bed access to adults ≥18 years old. OBJECTIVE: We evaluated artificial tanning behaviours of French teenagers (11-17 years old): sunless-tanning products, sunlamps and artificial tanning beds. METHODS: An anonymous questionnaire evaluating sunburn history, skin phototype, behaviours with sunless-tanning products and indoor tanning, and parents' behaviours was distributed to students enrolled in two middle and high schools in Antony, a typical city of the middle class French population, located in the Paris suburbs. RESULTS Among 713 teenagers (mean age: 13.5 years: male/female: 1.1) responding, more than half declared that it was important to be tanned during the summer, 1% reported having already used tanning pills, 9.9% tanning creams and 1.4% indoor tanning. Female teenagers significantly more frequently resorted to indoor tanning (P = 0.02), cited the importance of being tanned all year long (P < 0.0001), used tanning pills (P < 0.0001) or tanning creams (P < 0.006), and their parents relied on indoor tanning (P < 0.0001). Profiles of tanning-pill and -cream users were similar. Mean ages for the two groups were comparable. CONCLUSION: French regulations for indoor tanning seem quite effective. Our analyses revealed a typical teenager profile with sun-exposure risk behaviours, for example, indoor tanning, and use of tanning pills or creams. They could be a selective target for sun-protection information campaigns.

Fresh aromatic herbs containing methylchavicol did not exhibit the pro-oxidative effects of pure methylchavicol on a human hepatoma cell line, HepG2.

Methylchavicol (CH(3)-CV), an important aromatic constituent of different plants like tarragon and basils, has been shown to be carcinogenic by a mechanism yet unclear, although it has been reported that carcinogenicity of CH(3)-CV in rodent might be linked to its metabolic conversion into a genotoxic electrophilic metabolite generated through a two steps bioactivation pathway catalyzed by cytochrome P450 enzymes and sulfotransferases. The induction of carcinogenesis by certain agents has been associated with the generation of oxidative stress. The aim of the present study was to determine whether pure methylchavicol applied on a human hepatoma cell line, HepG2, could promote oxidative stress and might alter the expression of procarcinogenic biomarkers such as the drug-metabolizing enzyme (CYP2E1), the inducible form of nitric oxide synthase (iNOS) and might induce the expression of Cu/Zn-superoxide dismutase (Cu/Zn-SOD) and Mn-SOD that control the redox equilibrium of the cells. CH(3)-CV was shown to cause a significant induction of oxidative stress, as revealed by luminol-dependent chemiluminescence (LDCL) and to alter dramatically the expression of CYP2E1, iNOS and Mn-SOD, indicating that the toxic effect of CH(3)-CV could be mediated through a nitric oxide dependent mechanism. Under similar experimental conditions, the extracts from tarragon, chervil and basil did not induce such biological changes. These results provide evidence that the generation of an oxidative stress may be a significant event occurring during CH(3)-CV-induced toxicity. It also suggests that natural extracts containing different amounts of CH(3)-CV (tarragon, chervil and basil) did not elicit such toxicity and might contain compounds able to counteract this detrimental property.

Broad spectrum antibiotic activity of the skin-PYY.

Neuropeptide Y (NPY) and polypeptide YY (PYY) are two ubiquitous neuropeptides, found in brain and intestines, respectively, where they exert important regulatory functions. In this study, a new member of the YY family recently isolated from amphibian skin, skin-PYY (SPYY), is reported to inhibit irreversibly the proliferation of a broad spectrum of pathogenic microorganisms. NPY and PYY are shown to be endowed with the same activity. Their potency is similar to that of other antibacterial peptides which have been shown to exert their function by disintegrating the bacterial membrane. These findings and the fact that the C-terminal alpha-helical domain SPYY14-36, which is highly conserved among family members, was responsible for killing microorganisms and for permeation of phospholipid vesicles, suggested that the antibiotic activity may emerge via a membrane permeation mechanism. These findings also raise the question whether NPY and PYY exert in vivo a similar function in mammals.

Antigenic components of partially purified antigens of Leishmania donovani infantum recognized by sera from dogs with asymptomatic or active visceral leishmaniasis.

The antigenic components of a semipurified fraction of Leishmania donovani infantum were determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot analysis using 14 serum samples from dogs with symptomatic visceral leishmaniasis and 11 serum samples from apparently healthy dogs collected in an area endemic for canine visceral leishmaniasis (CVL). It was found that these antigens were composed of many polypeptides, among which seven components recognized by symptomatic CVL sera, had molecular weights of approximately 18, 28, 30, 33, 63, 70, and 72 kilodaltons (kD); two components of 63 and 70 kD were recognized by three of 11 healthly dog sera. These findings suggest that specific antigens induce humoral immune response in dogs with asymptomatic or active visceral leishmaniasis. Infected dogs are not readily identifiable by their symptoms. The potential interest of the immunoblot test for CVL diagnostic purposes is discussed.

Serodiagnosis and screening of canine visceral leishmaniasis in an endemic area of Corsica: applicability of a direct agglutination test and immunoblot analysis.

For effective control of visceral leishmaniasis caused by Leishmania infantum in the Mediterranean area, the detection of infected dogs is of utmost importance. To assess the suitability of a direct agglutination test (DAT) and immunoblot analysis in serodiagnosis and screening of infected dogs under field conditions, a study was performed on 113 dogs in an endemic area of Corsica. Twenty one of 22 parasitologically confirmed cases were correctly diagnosed by both tests, and 100% specificity was found when 11 dogs with other diseases were examined. Interestingly, eight of 80 apparently healthy dogs from the same area were found to be parasite-positive by the DAT test as well as by the immunoblot. Although both tests were equally sensitive and specific, based on both the feasibility of its application in field conditions and ease of performance, we consider the DAT to be more suitable for serodiagnosis and large-scale screening of infected dogs.

Nitric oxide production in human macrophagic cells phagocytizing opsonized zymosan: direct characterization by measurement of the luminol dependent chemiluminescence.

When differentiated into mature macrophages by the combination of all-trans retinoic acid and 1,25-dihydroxyvitamin D3, the human promonocytic cell lines U937 and THP-1 expressed inducible nitric oxide synthase (iNOS) transcripts. During their differentiation, the cells acquired the capacity to produce not only superoxide anion (O2.-) but also nitric oxide (.NO) in response to IgG (or IgE)-opsonized zymosan. The inhibitors of the iNOS pathway, aminoguanidine and NG-monomethyl-L-arginine (L-NMMA), suppressed the production of .NO and enhanced the steady-state concentration of O2.- determined. Conversely, superoxide dismutase (SOD) scavenged the O2.- released and increased the .NO-derived nitrite concentration detected. These data suggested a possible interaction between O2.- and .NO. In differentiated U937 (or THP-1) cells, IgG or IgE-opsonized zymosan induced a strong time-dependent luminol-dependent chemiluminescence (LDCL), which was abrogated by SOD and partially inhibited by aminoguanidine or L-NMMA. Since the iNOS inhibitors did not directly scavenge O2.-, LDCL determination in the presence or absence of SOD and/or iNOS inhibitors demonstrated a concomitant production of O2.- and .NO. These radicals induced the formation of a .NO-derived product(s), probably peroxynitrite (ONOO-), which was required to elicit maximal LDCL. Finally, LDCL measurement provided a convenient tool to characterize iNOS triggering and demonstrated an interaction between NADPH oxidase and iNOS products in human macrophagic cells phagocytizing opsonized-zymosan. These findings show that in activated macrophages, iNOS activity can be involved in LDCL and support the debated hypothesis of iNOS participation to the microbicidal activity of human macrophages.

Vaccination and treatment trials against murine leishmaniasis with semi-purified Leishmania antigens.

Antigens with molecular weight ranges of 94-67 kDa (LiF2), 30-20 kDa (LiF5), or below 20 kDa (LiF6), isolated from lysates of Leishmania infantum promastigotes by electroelution from polyacrylamide gels were injected into mice which were genetically either partially resistant (C57BL/6) or susceptible (BALB/c) to Leishmania infection. One month after the completion of the intravenous (C57BL/6) or subcutaneous (BALB/c) schedules, the mice were challenged with 1 x 10(3) L. major promastigotes. All mice immunized with LiF2, LiF5 and LiF6 were completely resistant. Furthermore, the C57BL/6 mice immunized with LiF2 resisted a second challenge with 1 x 10(4) L. major amastigotes. 5 months later, LiF2 antigen was used for immunotherapy of L. major leishmaniasis; parasites disappeared from the treated skin lesions, although ensuing systemic infection could not be averted.

Inhibition in vivo of both infective Leishmania major and L. mexicana amazonensis mediated by a single monoclonal antibody.

Monoclonal antibodies raised against a strain of Leishmania infantum isolated in Greece were produced and tested for their protective effect in an in vivo system (in BALB/C mice). A single monoclonal antibody, IgG2b isotype, can prevent the development of two Leishmania strains in vivo: one of L. major and one of L. mexicana amazonensis. This antibody-mediated protection may be dependent on complement.

Application of an in vivo culture system for rapid demonstration of anti-Leishmania activity of monoclonal antibodies.

In mice, infection with Leishmania by the subcutaneous route becomes evident after about 2 months. This delay impedes the selection of monoclonal antibodies able to interfere with the infectiousness of the parasite. Using an in vivo culture system--intraperitoneal injection of TG 180 sarcoma cells along with promastigotes or amastigotes--it was possible to define within 15 to 20 days a monoclonal antibody preventing the development of Leishmania. Pretreatment of promastigotes and amastigotes of several Leishmania species with a monoclonal antibody raised against Leishmania infantum prevented infection equally in either system. These cross-reactions may be of importance in designing new approaches of immunotherapy.

In vitro study of the anti-leishmanial activity of biodegradable nanoparticles.

Leishmania are obligate intracellular parasites, responsible for leishmaniasis. Leishmaniasis are transmitted via insect vector to vertebrate hosts including humans. The infection was reproduced in vitro with promastigotes which can infect murine resident peritoneal cells. Amphotericin B was incorporated into poly(D, L-lactide-co-glycolide) nanoparticles, biodegradable drug carriers, to allow specific targeting inside the cell. The interaction of the drug with infected cells was determined by exposing macrophage cultures to drug carriers. The toxic effects of polymeric drug carriers were defined prior to exposing cells to drug-loaded nanoparticles. For contact times up to 4h, cells tolerated polymer concentrations of 0.01%. The viability of parasites after treatment was determined. Infected macrophages were incubated at 26 degrees C (which allows the transformation of amastigote to promastigote) along with loaded and unloaded nanoparticles, as well as the free drug alone, and a count of the parasites in the medium was recorded. Anti-leishmanial activity was observed with drug-free nanoparticles. This activity may arise through the release of hydrogen peroxide following the activation of macrophages. The incorporation of amphotericin B did not enhance this effect. Interestingly, trehalose, a cryoprotector of the freeze-dried nanoparticles, altered parasite growth and activated macrophages.

Exploitation of parasite-derived antigen in therapeutic success against canine visceral leishmaniosis. Veterinary Group of Lupino.

In an attempt to obtain therapeutic success against canine visceral leishmaniosis, the potential of LiF2 antigen (Leishmania infantum-derived Fraction 2, 94-67 kDa), given alone or in combination with the chemotherapeutic agent N-methylglucamine antimonate, was compared with conventional chemotherapy with that drug. Absence of any parasite in direct microscopic examination of bone-marrow aspirates in treated dogs was considered a parasitological cure, i.e. therapeutic success. Results showed that the disappearance of clinical symptoms did not always indicate parasitological healing in dogs. The parasitological healing rates with chemotherapy and immunotherapy alone were 37.5% and 25% respectively, in contrast to the 100% cure rate observed with chemotherapy combined with immunotherapy. The development of a protective response in dogs, as measured by the in vitro leishmanicidal activity of monocyte-derived macrophages in the presence of autologous lymphocytes, was found to correlate well with the success of therapy. The overall findings of this study give an important insight into the immunotherapeutic strategy by which therapeutic success can be achieved in canine visceral leishmaniosis.

Immunization of dogs with a Leishmania infantum-derived vaccine.

A partially-purified extract of Leishmania infantum has been administered to healthy dogs. Post-immunization sera were found to neutralize the infectivity of L. infantum and to abate the development of L. major. Muramyl dipeptide and one of its derivates, murabutide, were the best adjuvants.

A monoclonal antibody against blood forms of Trypanosoma cruzi lyses the parasite in vitro and inhibits host cell invasion.

Monoclonal antibodies (mAbs) of the IgM isotypes were produced from mice immunized with blood forms of Trypansoma cruzi Y strain. Characterization of the epitope recognized by one of the mAbs, 164C11, as well as the effects of this mAb on complement-mediated lysis and host cell invasion are reported. Immunocytochemical analysis showed that the mAb was reactive with various strains of T. cruzi (Y, WSL, and Colombiana) as well as other trypanosomatids. The mAb 164C11 demonstrated a high complement-mediated lytic activity against bloodstream trypomastigotes, being more effective than chronic mouse serum. A protein with an apparent molecular weight of 72 kDa was detected by this mAb on all developmental stages of T. cruzi. Studies using periodate and endoglycosidase treatments suggested that the epitope is not a carbohydrate and seems to be located on the parasite membrane. In addition, preliminary results are presented, suggesting that the 72-kDa protein is involved in adhesion/or internalization of bloodstream trypomastigotes.

[Needle aspiration biopsy in the diagnosis of cutaneous leishmaniasis]. / Prélèvement par aspiration à l'aiguille dans le diagnostic de la leishmaniose cutanée.

The classic diagnostic procedure for cutaneous leishmaniasis is based on the examination of Giemsa-stained smears made from the fluid obtained by scraping the edges of the lesion with a lancet, or prepared with small plugs of superficial tissues. In this report, we compare the results given by this standard method with those obtained by the examination of needle aspirates. Aspirates are secured by injecting a few millimetres outside the external border of the lesion 0.3 to 0.5 ml of saline through a thin needle, rubbing the injured skin, and thereafter pulling back slowly the plunger. Amastigotes were found in all smears from needle aspirates, and in only 11 out 15 obtained by scraping. Aspirates were also more suitable for cultures of parasites.