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Proliferative vitreoretinopathy (PVR) is a complex process. It causes contractile fibrocellular membranes that may prevent retinal reattachment. PVR therefore remains one of the most severe complications of rhegmatogenous retinal detachment (RD), with an incidence of 5-11%, and is among the most frequent causes of surgical failure (50-75%). Its severity derives from the complexity of the surgery required to treat patients and from its uncertain anatomic and functional prognosis. The first step in preventing PVR is to identify patients at risk by means of clinical and/or biological factors such as the characteristics of retinal tears (large size, number) and detachment (preexisting PVR, extent), and the use of cryotherapy. Surgeons must therefore adapt their surgical approach to the risk of PVR. The study of animal models and the natural history of the condition in humans demonstrate the importance of early antiproliferative treatment in the early stage of the disease. Combining 5-fluoro-uracil and heparin in the vitrectomy infusion lowers the rate of postoperative PVR onset in patients with PVR risk factors. The evaluation of new molecules and new dosages will lead to a decisive step in the fight against PVR., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

The management of hand eczema, more readily called chronic hand dermatitis, is complex. This heaviness is related not only to the disease itself by its different clinical forms but also the multiplicity and diversity of etiological factors, triggering / maintaining or aggravating factors. The repeated therapeutic failures are ransom of incorrect information about the disease and its environment, a lack of clarity in the prescription and duration of treatment in general too short. The reference treatment is high potency topical steroids with or without occlusion for 4-8 weeks followed by alitretinoin 30 mg / day for at least 3-6 months with a monthly lipid and liver monitoring and mandatory monthly pregnancy test in women of childbearing. Associated measures and patient education are the cornerstones of successful treatment. Other alternative treatments such as phototherapy, methotrexate, cyclosporin, mycophenolate mofetil etc. can be considered in case of resistance or for clearing followed by topical treatments., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

Chronic hand eczema is a frequent cause of consultation. In Europe and Switzerland, it's one of the main reasons for patients to interrupt their profession. The etiology is pluri-factorial. Atopic patients are more likely predisposed. Pruritus, associated to pain and bleeding, is intense. Psychosocial consequences are huge, making this illness to an important public health problem. Topical treatment and UV-light are the main therapeutical strategy but the results are often disappointing. Recently, alitretinoine (9-cis retinoic acid) became the treatment of second choice with good response, allowing patients to preserve a good quality of life and their job.

A range of treatment options are available in rosacea, which include several topical (mainly metronidazole, azelaic acid, other antibiotics, sulfur, retinoids) and oral drugs (mainly tetracyclines, metronidazole, macrolides). In some cases, the first choice is a systemic therapy because patients may have sensitive skin and topical medications can be irritant. Isotretinoin can be used in resistant cases of rosacea. Unfortunately, the majority of studies on rosacea treatments are at high or unclear risk of bias. A recent Cochrane review found that only topical metronidazole, azelaic acid, and oral doxycycline (40 mg) had some evidence to support their effectiveness in moderate to severe rosacea and concluded that further well-designed, adequately-powered randomised controlled trials are required. In our practice, we evaluate our patients for the presence of two possible triggers, Helicobacter pylori infection and small intestinal bacterial overgrowth. When they are present we use adapted antibiotic protocols. If not, we use oral metronidazole or oral tetracycline to treat papulopustolar rosacea. We also look for Demodex folliculorum infestation. When Demodex concentration is higher than 5/cm(2) we use topical crotamiton 10% or metronidazole., (Copyright © 2011 Elsevier Masson SAS. All rights reserved.)

After an open preliminary study, two double-blind placebo-controlled randomized studies have confirmed the value of per os alitretinoin in the management of severe chronic hand eczema (CHE). The first showed dose-dependent efficacy and a response defined as "clear" or "almost clear" by 53% of the patients receiving 10-40 mg of alitretinoin per day for 12 weeks. In the second multicenter study (the Bach study), comparing the efficacy of a 12-week alitretinoin treatment (10 mg, 30 mg) to placebo for CHE, a "clear or almost clear" result was observed in 17% (placebo group), 28% (group alitretinoin 10 mg), and 48% (group alitretinoin 30 mg). The onset of action was also significantly shorter in the group treated with 30 mg of alitretinoin compared to the group treated with 10 mg. In a study of randomized retreatment versus placebo, 80% of the patients who were initially responders to alitretinoin and whose CHE had relapsed found "clear" or "almost clear" with alitretinoin 30 mg administered for 12-24 weeks compared to 48% with alitretinoin 10 mg. In all the studies, clinical tolerance was comparable and satisfactory, with the most frequent negative side effects being headache, flushing, and mucocutaneous signs identical to those compared with other retinoids. An increase in cholesterol and/or triglycerides was the most frequent biological side effect. Central hypothyroidism, with no clinical expression, was observed more rarely. These studies confirm that alitretinoin treatment can be envisaged as second-line therapy in adults with CHE that does not respond to well-observed treatment with class potent or very potent dermocorticoids., (Copyright © 2010 Elsevier Masson SAS. All rights reserved.)

The beginning of this century was marked, in our specialty as in other, by two revolutions: the routine use of molecular biology tools for a better prognosis of the disease (flt3 receptor duplication in AML, mutational profile of Ig genes in CLL, gene expression profile with ARN chips in aggressive lymphomas.), and the discovery of "intelligent" molecules, targeting the tumoral cell. In this category, the most appealing is the STI571 (Gleevec , Novartis), targeting the molecular abnormality of the cells expressing bcr-abl protein: CML, ALL Ph1(+). Other molecules targeting signal transduction proteins (ras farnesylation inhibitors for example) are already in clinical trials. The increasing therapeutic use of monoclonal antibodies is also to be cited, with a special mention concerning the rituximab, used in several B lymphoid pathologies, from lymphoma to autoimmune diseases. His very good tolerance permits his use in ambulatory patients, and his combination with chemotherapy or his linkage with radioactive elements render this molecule indispensable. The other side of these molecules is their incredibly high cost, explaining the uncontrolled expenses in 2001 of hospitals hosting hematology as well as oncology activities.

Retinoic acid (RA) and interferons (IFN) are negative regulators of cell proliferation. A number of clinical trials were thus carried out in cancer therapy with RA and/or IFN. In vitro and in vivo, their combination leads to a more potent cell growth inhibition. Moreover, RA and IFN act cooperatively to increase the expression of many IFN-stimulated genes, leading also to a higher cell differentiation and inhibition of viral replication. However, the molecular mechanisms by which RA and IFN potentiate each other are not fully understood. The cooperative effects by RA and IFN are mediated through multiple pathways. RA causes the induction and secretion of IFN alpha. RA also stimulates the IFN regulatory factor gene expression (IRF1 and p48). Additional mechanisms could be involved as RA increases the level of signal transducing activators of transcription (Stat) proteins, and thus enhances the IFN-induced Stat activation.

Acute promyelocytic leukemia (APL) originate from chromosomal translocations generating two types of fusion proteins both involving the retinoic acid receptor alpha (RAR alpha) and either the gene PML (t(15;17)) or PLZF (t(11;17)). Recent publications cast a new light on the detailed molecular mechanism underlying the oncogenic activity of these fusion proteins which block myeloid terminal differentiation by recruiting histone deacetylases to the promoters of target genes through co-repressor proteins. They also explain the different responses to treatment by all-trans retinoic acid (ATRA) of these two variants which are otherwise clinically indistinguishable.

Acute promyelocytic leukaemia is a key model system in cancer biology. Its exquisite sensitivity to retinoic acid constitutes the first example of differentiation therapy. The PML/RAR alpha fusion protein generated by the t(15; 17) translocation is the molecular basis of transformation. PML/RAR alpha induces transformation most likely through a dominant negative interference with the function of nuclear receptors leading to a differentiation block. The fusion protein also delocalizes PML and other nuclear body antigens and this alteration of nuclear protein traffic seems to play a role in growth control and apoptosis. The clinical response of this disease to retinoids and arsenic trioxide, both of which induce the degradation of the fusion protein, constitute the first example of a therapy directly targeted to a specific genetic lesion in a human cancer.

Acute promyelocytic leukaemia is a key model system in cancer biology. Its exquisite sensitivity to retinoic acid constitutes the first example of differentiation therapy. The PML/RAR alpha fusion protein generated by the t(34, 35) translocation is the molecular basis of transformation. PML/RAR alpha induces transformation most likely through a dominant negative interference with the function of nuclear receptors leading to a differentiation block. The fusion protein also delocalises PML and other nuclear body antigens and this alteration of nuclear protein traffic seems to play a role in growth control and apoptosis. The clinical response of this disease to retinoids and arsenic trioxide, both of which induce the degradation of the fusion protein, constitute the first example of a therapy directly targeted to a specific genetic lesion in a human cancer.

The treatment of acne is based upon simple pathogenic arguments, but needs to be adapted to the type of acne. Patients must always be informed that it is long and difficult and that no significant response will be expected before 2 to 3 months of regular treatment. The authors present the different therapeutic agents and strategies. Isotretinoin should be used only in severe acne after failure of at least 3 months of a well conducted classical treatment and in nodulo-cystic acne; because of its major side effect of teratogenicity its use in adolescent girl's requires pregnancy testings before and during treatment and an effective contraception.

Introduction: Adapalene is a new chemical entity with retinoid activity., Patients and Methods: 0.1 p. 100 adapalene gel (Différine gel), 0.03 p. 100 adapalene gel and a commercially available 0.025 p. 100 tretinoin gel (Aberel gel) were compared in 89 male and female patients with acne., Results: Inflammatory, non inflammatory, total lesion counts, and the global facial acne grade regularly decreased as a function of time in the three treatment groups. No statistically or clinicaly significant differences were observed for these parameters between 0.1 p. 100 adapalene gel and 0.025 p. 100 tretinoin gel following a 12-week treatment. Conversely, both of these gels were significantly more effective than 0.03 p. 100 adapalene gel with regards to inflammatory and total lesion counts, and the global facial acne grade. The differences of efficacy seen between both adapalene gels demonstrate a dose-dependent activity of the drug in the topical treatment of acne. The three products induced retinoid-like skin irritation with significant differences in intensity in favour of adapalene for erythema, dryness, scaling and burning after application and in favour of tretinoin for persistent burning. No treatment-related medical events were reported and adapalene plasma levels were lower than 0.15 ng/ml (limit of detection of the analytical method)., Conclusions: The topical treatment of acne with adapalene gels was found to be safe and effective, with a dose-related response. The efficacy of 0.1 p. 100 adapalene gel and of 0.025 p. 100 tretinoin gel are not different but skin tolerance of 0.1 p. 100 adapalene gel is superior.

These next years, many anticancer drugs will be available with new mechanism of action. The taxoïd compounds: Taxol and Taxotere have been judged efficous in the treatment of advanced ovary and breast cancers. Also, DNA-Topoisomerase I inhibitors, a new enzyme molecular target, will expand solid tumors therapeutic strategies. The adenosine analogs represent the xnewest advances in hematology: fludarabine becomes the second line treatment for chronic lymphoïd leukemia, cladribine the reference treatment for hairy cell leukemia. At least, all-trans retinoïc acid has changed acute promyelocytic leukemia pronostic by differentiating tumor cells, and open a very new way of cancer treatment. All these agents are the first compounds available, others are still in development. They, all, are benefit of a productive research.

Myeloblastin (mbn) is a serine protease involved in the control of growth and differentiation of human leukemic cells. In the promyelocytic-like human leukemia cell line HL-60 this protease is inhibited during retinoic acid (RA) induced differentiation. The t(15;17) translocation, specifically associated with the human acute promyelocytic leukemia (APL), fuses the retinoic acid receptor alpha (RAR alpha) to a novel gene PML generating the hybrid protein PML-RAR. We have shown that while mbn was early down-regulated in HL60 cells treated with all trans RA, the inhibition of this gene was considerably delayed in NB4 cells, which carry the t(15;17) translocation, upon treatment with the same inducer. This observation suggested that the changes in the myeloblastin regulation by RA found in NB4 cells could be ascribed to the presence of the fusion protein PML-RAR. To verify this hypothesis we have cloned the putative promoter region of mbn gene. Transactivation properties of endogenous retinoic acid receptors on this region have been tested in transfection experiments of HL60 and NB4 cell lines before and after treatment with all trans RA. We found that RA induced a significant inhibition of the luciferase reporter gene in HL60 cells. In contrast, a strong stimulation of luciferase activity was observed in NB4 cells treated with RA. The analysis of the promoter region allowed us to identify a new response element for retinoic acid receptors, named mREpal, which is probably affected by the product of t(15;17) translocation.

It has been shown in vitro that retinoids and especially all-trans retinoic acid (ATRA) were able to induce maturation of malignant cells from patients with acute promyelocytic leukemia (APL). Clinical studies have confirmed in vitro observations. Oral administration of ATRA is able to induce complete remissions in the majority of APL patients, either treated de novo or after failure of conventional chemotherapy. Complete remission are observed by a differentiation process and ATRA therapy in APL represents the first model of differentiation therapy. The major adverse effect of ATRA treatment is the occurrence in some cases of a "retinoic acid syndrome" associated with rapidly, progressive rise of leukocytes. This syndrome is corrected by the addition of chemotherapy. A progressive acquired resistance appears during ATRA treatment and for this reason post remission chemotherapy is indispensable. The superiority of the combination of ATRA+chemotherapy over chemotherapy alone for the incidence of relapse and for survival duration has been established in a randomized European trail (APL 91).

A randomized study was conducted to evaluate the effect of tretinoin and patient tolerance to treatment with topical applications in series of 20 cases of smoking-related or traumatic oral keratoses leukoplakia and of 20 cases of lichen planus. In each group, patients applied the topical ointment containing tretinoin (10 patients) or placebo (10 patients) twice daily. Clinical outcome was evaluated on the basis of the surface area of the lesion, measured monthly during treatment, as compared with the area observed at treatment onset. After 4 months treatment, there was a significant decrease in the surface area of the lesion in the patients with lichen planus (p < 0.02): 94 p. 100 in the tretinoin group versus 21.4 p. 100 in the placebo group. In patients with leukoplakias, there was also a very significant reduction in the surface area of the lesion after 4 months of treatment (p < 0.001): 80 p. 100 in the tretinoin group and 16 p. 100 in the placebo group. Tolerance to treatment was generally good despite a few complaints of quite temporary burning sensation at application rapidly resolutive.

In earlier work, we demonstrated that 0.1 p. 100 topical tretinoin is clinically effective and well tolerated compared with placebo for the treatment of oral leukoplakia and oral keratosic or erythematous lichen planus. Here we aimed to complete this clinical protocol with histological and biochemical analyses comparing the biopsy specimens collected at inclusion and those collected after 4 months of treatment. Histological results were based on changes in keratinization observed between onset of treatment and 4 months treatment. Biochemical studies included the use of antibodies (anti-cytokeratins 10-11, anti-filaggrine) for the immunohistochemical evaluation of keratinization and 2-dimensional gel electrophoresis for measuring cytokeratins. In patients with lichen planus, histological changes during treatment showed that, in the 10 patients in the tretinoin group, keratinization disappeared in 6 and decreased significantly in 3. Immunohistochemistry revealed that cytokeratins 10-11 and filaggrin disappeared in 57 p. 100 of the patients treated with tretinoin versus 25 p. 100 in the patients given placebo. Bidimensional gel electrophoresis showed that cytokeratins 1, 2, 10 and 11 disappeared only in the tretinoin group (60 p. 100 of the cases). In patients with leukoplakia, histological changes during treatment showed that, in the tretinoin group, keratinization disappeared in 5 cases and decreased in 5 others. Immunohistochemistry revealed that cytokeratins 10-11 disappeared in 30 p. 100 of the patients treated with tretinoin versus 25 p. 100 in the placebo group. Bidimensional electrophoresis demonstrated that cytokeratins 1, 2, 10 and 11 disappeared in 43 p. 100 of the patients treated with tretinoin.

Viscosity values of marrow cells from patients suffering from acute promyelocytic leukemia (acute myeloid leukemia of type 3) have been determined before and during a treatment with all-trans retinoïc acid (active metabolite of the vitamin A, inducing cell differentiation and maturation). Evaluated from aspiration tests into a glass micropipette, the marrow cell viscosity has been compared to that of normal neutrophils. Results seem to point out that the induced hyperleucocytosis is favoured by both a low standard deviation of pathological cell viscosity and a cell viscosity value close to that of normal neutrophils. The systematic study of cell viscosity could therefore help the clinicians to individualize the treatment.

All trans retinoic acid (ATRA) in the treatment of acute promyelocytic leukemia is the first model of differentiation therapy in malignancies, and represents the first strict correlation between a genetic defect and a specific treatment. In this disease the association of differentiating agents and chemotherapy gives much better results than each type of treatment (differentiating agent or chemotherapy).

Vitamin A acid has been used for 20 years in the local treatment of acne. In 1986, Kligman published a description of the efficacy of this molecule against skin ageing. In 1987, we began a study which is still in progress. It is intended to confirm the beneficial effects already observed in photosenescence and to demonstrate them by non-invasive methods and by standardized photographs. This study was randomized and carried out under double blind. Each patient acted as her own control. The concentration administered was 0.025 per cent for 6 months and then 0.05 per cent. The patient was followed up every month for 6 months and then every 4 months. The results demonstrated a reduction in the number and depth of the wrinkles and a regression of the pigmented spots. Safety was excellent and all the patients were highly satisfied with the treatment.

We have previously shown that all-trans retinoic acid therapy is an alternative therapy for acute promyelocytic leukemia (AML3) via differentiation of the leukemic cells. The t(15;17) translocation is specifically found in this leukemia. We and others have shown that through this translocation the RAR alpha gene is rearranged and its expression altered in AML3 cells. The gene is truncated and fused to a novel gene (PLM). This results in a fusion protein whose transactivating properties may be implicated in the leukemogenesis of this disease. Retinoic acid cytoplasmic binding proteins (CRABP and CRBP) are not detected by PAGE chromatography in normal or malignant hematopoietic cells. During all-trans RA therapy, a) all-trans RA plasma concentrations are within in vitro differentiating concentration (med. 0.4 microgram/ml); b) increased expression of the normal remaining RAR alpha allele is rapidly observed and may explain the paradoxical induction of RA differentiation in these cells; c) CRABPII is induced in the bone marrow cells of AML3 patients and remains detectable 1 month after withdrawal of RA. AML3 in relapse after RA therapy is always less sensitive to RA in vitro and in vivo. Our data suggest that modification of the metabolisation pathways of RA may be one of parameters linked to this resistance. It appears that the efficacy of all-trans RA is the resultant of multiple parameters (RA concentration, ratio of PML/RAR alpha transcripts to normal RAR alpha, CRABP) which need to be defined to efficiently monitor all-trans RA therapy in APL.

Retinoids are natural and synthetic analogues of vitamin A. They have a marked influence on the differentiation of epithelial tissues by modifying membrane glycoconjugates and by acting through cytosolic and nuclear mechanisms like steroid hormones. Their clinical and biological toxic effects are numerous, but they are usually benign and reversible. However the possibility of teratogenic effects requires close monitoring of female patients. Etretinate is particularly effective in disorders of keratinisation (psoriasis, ichthyosis) whereas isotretinoin is the best known therapy of severe acne. Moreover the possible role of retinoids in the prevention and treatment of certain cancers gives hopeful prospects.

Avitaminosis A, applied on deficient rats receiving retinoic acid leads to an important decrease of thymidine incorporation in testicular DNA in vivo as well as in vitro. On the contrary uridine incorporation in RNA is considerably increased in vitro as well as in vivo. The function of ribosomes, as measured by the aggregation ability in the polysomes, is not altered by vitamin A deficiency. From these results one can say that the degenerescence of rat testicle is accompagnied by a decrease of DNA anabolism and a stimulation of RNA anabolism due to an increase of its catabolism (compensatory synthesis).

Observations of 3 different great ichthyotic disorders, no longer responding to local keratolytics and to oral vitamin A are reported: a case of erythrokeratoderma variabilis, one of ichthyosiform erythroderma, and one of bullous ichthyosiform hyperkeratosis. After a week of oral treatment by the ethylester retinoid (Ro 10-9359), the hyperkeratotic component of each disease already improved dramatically. A maintenance treatment had to be continued. With equal or superior keratolytic effects, the retinoid has lower toxicity and less important side-effects than retinoic acid itself. The ethylester retinoid is nowadays the choice oral treatment in these great hyperkeratotic disorders.

A multicentric trial involving ten dermatological departments was conducted to evaluate the efficacy and tollerance of ANTIBIO-ABEREL (an association of Tretinoin and Erythromycin base) in 347 patients with persistant acne. Complete healing or considerable improvement was obtained in 85% of cases. This new treatment was active against both inflammatory lesions (papules and pustules) and retentional elements (microcysts and open comedones). It was also rapidly active, as very favorable results were obtained in ten weeks or less, in more than half of the cases. The tolerance was remarkable (less than 1% of cases had to interrupt treatment). This product represents an important progress as compared to Tretinoin alone. No other local or systemic therapy, especially long term antibiotherapy, is required.

56 patients with nodulocystic acne, hidrosadenitis (2 cases) and steatocystoma multiplex (2 cases) were treated with oral isotretinoin. 52 patients cleared completely or were much improved without local treatment; 2 failures involved patients with steatocystoma, while 2 patients with ano-inguinal lesions were only improved. 19 patients received a dose of 0.5 mg/kg/day for six months; in 37 patients the dose was adapted to the initial response but did not exceed 1 mg/kg/day. Reversible elevated triglyceride concentration was observed in 5% of the patients. 18 patients were followed up and 4 (22%) presented moderate relapses.

Our study related to degenerescence of testes in vitamin A deficient rats led to the following observations : decrease of DNA, RNA on one hand and AMP, ADP and ATP on the other hand. These observations are considered as related to decrease of DNA polymerase activity.