Microsatellite-based high density linkage map in oil palm (Elaeis guineensis Jacq.).

A microsatellite-based high-density linkage map for oil palm (Elaeis guinensis Jacq.) was constructed from a cross between two heterozygous parents, a tenera palm from the La Me population (LM2T) and a dura palm from the Deli population (DA10D). A set of 390 simple sequence repeat (SSR) markers was developed in oil palm from microsatellite-enriched libraries and evaluated for polymorphism along with 21 coconut SSRs. A dense and genome-wide microsatellite framework as well as saturating amplified fragments length polymorphisms (AFLPs) allowed the construction of a linkage map consisting of 255 microsatellites, 688 AFLPs and the locus of the Sh gene, which controls the presence or absence of a shell in the oil palm fruit. An AFLP marker E-Agg/M-CAA132 was mapped at 4.7 cM from the Sh locus. The 944 genetic markers were distributed on 16 linkage groups (LGs) and covered 1,743 cM. Our linkage map is the first in oil palm to have 16 independent linkage groups corresponding to the plant's 16 homologous chromosome pairs. It is also the only high-density linkage map with as many microsatellite markers in an Arecaceae species and represents an important step towards quantitative trait loci analysis and physical mapping in the E. guineensis species.

Development, characterisation, and across-taxa utility of oil palm (Elaeis guineensis Jacq.) microsatellite markers.

The results of the development of oil palm (Elaeis guineensis Jacq.) microsatellite markers are given step by step, from the screening of libraries enriched in (GA)n, (GT)n, and (CCG)n simple-sequence repeats (SSRs) to the final characterisation of 21 SSR loci. Also published are primer sequences, estimates of allele size range, and expected heterozygosity in E. guineensis and in the closely related species E. oleifera, in which an optimal utility of the SSR markers was observed. Multivariate data analyses showed the ability of SSR markers to efficiently reveal the genetic-diversity structure of the genus Elaeis in accordance with known geographical origins and with measured genetic relationships based on previous molecular studies. High levels of allelic variability indicated that E. guineensis SSRs will be a powerful tool for genetic studies of the genus Elaeis, including variety identification and intra- or inter-specific genetic mapping. PCR amplification tests on a subset of 16 other palm species and allele-sequence data showed that E. guineensis SSRs are putative transferable markers across palm taxa. In addition, phenetic information based on SSR flanking region sequences makes E. guineensis SSR markers a potentially useful molecular resource for any researcher studying the phylogeny of palm taxa.

Does manganese protect cultured human skin fibroblasts against oxidative injury by UVA, dithranol and hydrogen peroxide?

Reactive oxygen species (ROS) are involved in the mechanism of photoaging and carcinogenesis. Skin is endowed with antioxidant enzymes including superoxide dismutases (SOD): cytosolic copper zinc SOD and mitochondrial manganese SOD. The aim of our study was to estimate the protective effect of manganese against oxidative injury on cultured human skin fibroblasts. Dithranol, hydrogen peroxide and UV-A radiation (375 nm) were employed as oxidative stressors. The supply of manganese chloride produced an increase in cellular content of this element up to 24 fold without concomitant elevation of MnSOD activity. Nevertheless, manganese protects cells against two of the three ROS generating systems assessed, namely hydrogen peroxyde and UV-A. This protective effect depends on the concentration of manganese in the medium, 0.1 mM and 0.2 mM protect against UVA cytotoxicity, only 0.2 mM protects against H2O2 cytotoxicity.

Clinical evaluation of topical isotretinoin in the treatment of actinic keratoses.

BACKGROUND: Retinoids have been shown to improve the manifestations of skin photodamage, including actinic keratoses. OBJECTIVE: The efficacy and tolerability of isotretinoin 0.1% cream in the treatment of actinic keratoses were evaluated in a randomized, double-blind, placebo-controlled, parallel-group study. METHODS: One hundred patients were randomly assigned to treatment with 0.1% cream or vehicle twice daily for 24 weeks to the face, the scalp, and the upper extremities. Patients were assessed every 4 weeks by the investigators, who counted and recorded the number of lesions in each treatment area. The 93 patients who had at least one postbaseline assessment were included for efficacy analysis. Local tolerability was evaluated at each study visit. RESULTS: On the face, the reduction in number of actinic keratoses (mean +/- SEM) at the end of treatment was greater for patients treated with isotretinoin (3.9 +/- 0.6, i.e., 66% of patients with a reduction > 30%) than with placebo (1.7 +/- 0.5, i.e., 45% of patients with a reduction > 30%); this difference was statistically significant (p = 0.001). No significant drug effect was seen for lesions on the scalp or upper extremities. Mild to moderate local reactions with isotretinoin abated with reduced treatment frequency. CONCLUSION: Our results suggest that isotretinoin 0.1% cream cannot compete with more rapid treatments of actinic keratoses. However, its effect on facial lesions may be beneficial during long-term treatment of associated sun-damaged skin.

Protective effect of selenium and zinc on UV-A damage in human skin fibroblasts.

Ultraviolet A radiation participates in cytotoxicity and carcinogenesis of the skin by a mechanism involving the generation of reactive oxygen species. Endogenous antiradical defense systems utilize metalloenzymes including Se-dependent glutathione peroxidase and Cu and Zn superoxide dismutase. The aim of the present work was to determine the protective effect of two trace elements, Se and Zn, on cultured human diploid fibroblasts exposed to UV-A radiation (broad-spectrum source with a maximum intensity at 375 nm). Selenium in the culture medium (0.1 mg/L) in the form of sodium selenite increased the synthesis and activity of glutathione peroxidase by 60.5% in the absence of exposure to UV-A radiation and by 35% after irradiation with 5 J/cm2 (P = 0.043). The presence of this element significantly increased the survival of UV-A-irradiated fibroblasts (P < 0.0001). This confirms the essential role of Se in the detoxifying activity of the enzyme. In addition, thiobarbituric acid-reacting substances (TBAR), which are lipid peroxidation markers, decreased in the presence of exogenous Se: -19% and -22% without irradiation and after irradiation with 5 J/cm2 (P = 0.056). When Zn was added at the dose of 6.5 mg/L as ZnCl2, fibroblasts subjected to oxidizing stress induced by UV-A were protected from cytotoxicity (P < 0.0001). The TBAR production decreased significantly: -33% without irradiation and -34% after irradiation with 5 J/cm2 (P = 0.008). Superoxide dismutase activity, however, decreased after supplementing with Zn: -26% without irradiation and -20% after UV-A irradiation (P = 0.017). The antioxidant properties of Zn are thus apparently independent of superoxide dismutase activity.

[Plasma levels of psoralens after celery ingestion]. / Etude des taux plasmatiques de psoralènes après ingestion de céleri.

Psoralens are photosensitizing substances present in many vegetables, some of which are routinely consumed. These vegetables are responsible for contact phytophotodermatitis, but it was agreed that they did not produce photodermatitis when taken orally. Ljunggren has recently questioned this concept by reporting a case of phototoxic accident which occurred after ingestion of 450 grams of celery roots (Apium graveolens). In a study in healthy volunteers we looked for psoralens in blood and analyzed the cutaneous photosensitivity by the minimal phototoxic doses (MPD) method, after ingestion of celery in large amounts (500 grams and more). Plasma concentrations of psoralens were inexistant in all subjects and at all sampling times, and no phototoxic reaction was detected by MPD. Celery roots, therefore, do not seem to be photosensitizing, even after ingestion in large amounts, but they might increase the risk of phototoxicity in PUVA-therapy. The same applies to fennel and parsnip.

[Systemic mastocytosis: incidence and risks of vasomotor seizures]. / Mastocytose systémique: fréquence et risques des crises vasomotrices.

We report on 9 cases of systemic mastocytosis which underline the frequency and the potential severity of this disease. All patients had intercritical signs (usually urticaria). Seven patients had also typical crises with flush and vascular collapses are observed together, doctors should measure histamine blood level and perform correct biopsy.

[Skin diseases with photosensitivity]. / Dermatoses avec photosensibilité.

Skin diseases associated with photosensitivity are numerous and may be divided into three main groups: photo-aggravated dermatoses, genophotodermatoses and metabolic photodermatoses. Photo-aggravated dermatoses are autonomous skin diseases in which exposure to sunlight may make the disease worse or precipitate its onset and/or its progressiveness; this group includes lupus erythematosus, autoimmune bullous diseases, acantolytic dyskeratoses, acne vulgaris, rosacea and cutaneous lymphoid infiltrates. To these must be added photosensitive forms of autonomous dermatoses such as atopic dermatitis, psoriasis, herpes labialis, erythema multiforme, granuloma and disseminated superficial actinic porokeratosis. Genophotodermatoses are genodermatoses which are made photosensitive by a recognized or as yet unidentified deficiency of the natural photoprotection system. In this group are albinism, vitiligo, xeroderma pigmentosum and poikiloderma. Metabolic photodermatoses are diseases in which photosensitization reactions, often revealing, are due to the accumulation in the skin of an endogenous chromophore as a result of a congenital (porphyria) or acquired (pellagra) enzymatic disorder.

Psoralen plus ultraviolet A in the prophylactic treatment of benign summer light eruption.

We report the results of a French multicentre study to evaluate the efficiency of psoralen plus ultraviolet A (PUVA) therapy in the prophylactic treatment of benign summer light eruption (BSLE) and to establish the optimal protocol of radiation. Nine photobiology centres took part in this study; 83 patients (76 of them women) were evaluated. The radiation protocols were as follows: oral psoralen (8-methoxypsoralen; 0.6 mg/kg) was taken at each session; the starting dose of UVA radiation was determined according to skin type, with increments of 0.5 J/cm2 every 2 sessions. The subjects were randomized to receive 10-20 sessions 3 times per week. PUVA therapy was very effective: 68 patients (82%) reported total protection from BSLE. Four patients (5%) showed progress. Only 13% showed no improvement. The satisfactory results were not correlated with either the number of sessions or the J/cm2 of UVA. The intensity of tanning after the PUVA sessions did not appear to predict cure. Thirty-six percent of the patients had adverse reactions to treatment, including erythema, pruritus and triggering of BSLE. However, these effects only required the treatment to be stopped in 2% of the cases (for severe pruritus). The results in the various centres were similar.

UV-induced squamous cell carcinomas in the hairless mouse. Morphological characteristics and transplantation in the syngenic and nude mouse.

Squamous cell carcinomas were induced by UVB in the hairless mouse HRO hr/hr. Twelve mice were irradiated three times a week at a dose of 0.19 J/cm2. The average latency period for the appearance of the first tumour is 16 weeks and by the 21st week, tumour incidence is 100%. Further observation of these tumours shows that their growth is independent of irradiation dose and that the tumours continue to appear even after cessation of irradiation. Histological and cytological examination of these tumours show them to have characteristics of malignancy. Transplantation in athymic mice suggests that UVB provokes immune deficiencies in hairless mice similar to those seen in conditioned nude mice.

[Problems posed by the therapeutic use of photosensitizers in dermatology]. / Problèmes posés par l'utilisation thérapeutique des photosensibilisateurs en dermatologie.

Three phototherapeutic regimens with photosensitization are now used in dermatology: PUVA (psoralen + UVA), TUV (crude coaltar + UV), PRT (phototherapy with hematoporphyrin derivative). The efficiency of PUVA and TUV is well known in several dermatoses. PRT is now being tested experimentally. For TUV, the lack of a standardized regimen does not allow a clear-cut evaluation of the therapy. For PUVA, late side-effects, particularly carcinogenicity have to be considered. To improve efficiency and minimize the side-effects of PUVA some procedures, such as association with retinoïds, pharmaco-kinetic studies for individual adaptation of the therapeutic regimen and the use of new less mutagenic psoralens are helpful. The persistent phototoxicity following treatments with hematoporphyrin derivative constitutes the major side-effect observed, for this phototherapy.

Buschke-Ollendorf syndrome. An electron microscopic study.

Two identical twins with the Buschke-Ollendorf syndrome (dermatofibrosis lenticularis disseminata with osteopoikilosis) are described. Ultrastructurally elastic fibers show clumps of electron-lucent elastin material coated with fine fibrils. The fibroblasts show enlarged endoplasmic reticulum containing abnormal fibrillar material. Juvenile elastoma seems to be a better term than dermatofibrosis. The pathogenesis of the elastic defect is discussed.